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PARIS UNIVERSAL EXPOSITION, 1867. 
REPORTS OF THE UNITED STATES COMMISSIONERS 



MACHINERY AND PROCESSES 



THE INDUSTRIAL ARTS, 



AND APPARATUS OF 



THE EXACT SCIENCES. 



UY 



V 

FREDERICK A. P. BARNARD, LL. D. 5 

UNITED STATES COMMISSIONER. 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE, 

1 SG9. 



\ 



PREFACE 



The following report is an attempt to comply with that portion of the 
instructions issued by the Secretary of State to the Commission of the 
United States to the Exposition of 1867, which required a report to be 
prepared upon the new inventions in the useful arts illustrated in the 
Exposition. It need hardly be remarked that an entirely satisfactory 
execution of a task like that here presented could be reasonably expected 
only from the co-operation of a number of individuals, severally quali- 
fied, by previous familiarity with the different departments of industry 
represented, to appreciate the merits of the various objects subjected to 
their examination. The preparation of the required report was there- 
fore, originally, very properly confided to a committee ; but the plan of a 
joint report, at first contemplated, was found in the end to be impracti- 
cable, and was accordingly abandoned. Some members of the committee 
preferred to direct their attention to the study of special subjects, and 
the general duties imposed on the committee devolved at length upon 
the present reporter alone. This statement is felt to be necessary in 
explanation, or rather, perhaps, in justification, of an attempt on the 
part of the reporter to execute a task not willingly assumed by him, and 
which he found no encouragement to undertake in the consciousness of 
special qualification. 

A large portion of this report was prepared during the continuance of 
the Exposition, but the amount of labor thrown upon the reporter be- 
yond the extent of his original anticipation protracted the work of its 
completion until after the close. 

To the duties originally assigned to the committee on the useful arts 
was added, at a late period, that of reporting on the objects exposed in 
Class XII, embracing " Instruments of Precision, and Apparatus of In- 
struction in Science." The concluding chapters of the report are devoted 
to this interesting subject. A fall description of the Exposition in this 
class would occupy a much larger space than it has been found possible, 
or than it would have been p roper, to devote to it here. It may, how- 
ever, be said generally of that magnificent display, that it was made up 
in great part of instruments already well known ; although it is probable 
that there has never before been collected together in one spot so large 
a number of their kind, on which the highest order of artistic skill had 
so thoroughly exhausted itself. 

It remains only for the reporter to express his indebtedness to the 
Commissioner General, Mr. Beck with, for the many courtesies received 
from him throughout the continuance of the Exposition, and subse- 
quently; and to bear his cordial testimony to the ability, efficiency, im- 



IV PREFACE. 

partiality, and firmness, with which that officer discharged his always 
burdensome and often delicate duties ; as well as to the fidelity with 
which he protected the interests of his countrymen, even in cases in 
which he knew that his services were not appreciated. This is the least 
that can be said to the honor of one who had more than an equal share in 
the common lot of men in public places of being often misunderstood 
and oftener misrepresented; but who, unmoved by praise or blame from 
interested or irresponsible sources, followed silently and steadily the 
dictates of his judgment and his convictions of duty, and trusted to 
time for that sure vindication of his course which it has at length 
abundantly brought. 
Columbia College, New York, June, 1869. 



CONTENTS 



THE INDUSTRIAL ARTS. 

CHAPTER I. 

THE RELATION OF INVENTION TO INDUSTRIAL PROGRESS. 

Multiplicity of machines and industrial processes at the Exposition — Incessant modifications 
and improvements resulting from the division of labor — Inventions of great industrial 
importance are rare — Examples of such — The cotton-gin : its industrial, social, and politi- 
cal consequences — The steam-engine, and the industrial revolutions resulting from it — Pro- 
ductive power of industry limited by amount of disposable force — Handling and forging 
armor plates and other gigantic objects by the aid of steam — Precision of mechanical pro- 
cesses aided by steam — Examples of degree of refinement of mechanical accuracy — Whit- 
worth's true planes and gauges — Machine tools — Influence of the steam-engine upon the 
wealth and power of Great Biitain — Discovery and invention : their relations — Inventions 
directly affecting the moral and intellectual character of the human race — The printing 
press — The electiic telegraph — Different classes of inventions. — pp. 1-25. 

CHAPTER II. 
MOTORS. 

Hot-air engines — Advantages and disadvantages — Classification — Tkeoretic limit of economy 
— Ericsson's hot-air engine — Shaw's — Belou's — Roper's — Lauberau's— Wilcox's — Fran- 
chot's — Inflammable gas-engines — Otto and Langen's — Lenoir's — Hugon's — Ammoniacal 
gas-engines — Frot's — Delaporte's — Rotary steam engines — Behrens's — Pillner and Hill's — 
Scheutz's — Thompson's — Root's square piston engine — Hydraulic motors — Water-pressure 
engines — Carre t, Marshall & Company's engine — Perret's w r ater engine — Coque's — Rams- 
bottom's — Water-wheels — Turbine wheels — Fourneyron's turbine — The Girard free tur- 
bine — Turbines of Brault & Beihouard — Girard's hydraulic pivot — Aerial motors — Elec- 
tro-magnetic engines — Cazal's — Birmingham Company's— Kravogl's. — pp. 25-127. 

CHAPTER III. 

TRANSMISSION OF FORCE. 

Importance of the problem— Loss usually incurred in transmission— Example of Huelgoat — 
At Niagara — Hirn's telodynamic cable — Difficulties encountered by the inventor — How 
extensively introduced — Percentage of power delivered — Comparison with common modes 
of transmission— Calles's hydro-aero-dynamic wheel — In what respect original — Mechanical 
principal involved — Inventor's estimate of economy — Transmission of force by means of 
air highly compressed— Experiments at Coscia on resistance of tubes to flow of air— Laws 
deduced — Absolute and relative resistances — Increase of power without increase of resist- 
ance — Compressors at Bardonneche — Comparisons between results and the compressing 
force employed — Transmission of force by air and by cable compared. — pp. 128-150. 



VI COXTEXTS. 

CHAPTER IV. 

ACCUMULATION OF FORCE. 

Accumulation of force by compression of water — Sir William Armstrong's method — Accu- 
mulator of Gouin & Co. — Accumulation in fly-wheels — The Mahovos : a contrivance for 
the promotion of economy in railway transportation — Its construction — Illustration of the 
advantages to be derived from its use — Application of the Mahovos as a brake. — pp. 151- 
161. 

CHAPTER V. 

MEASURE OF FORCE. 

Mechanical contrivances for measuring the force of prime movers — Prony's friction dynam- 
ometer — Taurines's dynamometer — Method of registering its indications — Bourdon's 
dynamometer — Hirn's pandynamometer — Torsion of driving-shafts — The distortion of 
parts of machines made to indicate the amount of strain — Two methods of accomplishing 
the result : the mechanical and the electiical — Importance of this invention to the mechan- 
ical engineer. — pp. J 62-168. 

CHAPTER VI. 

DIRECT APPLICATIOXS OF FORCE. 

Machines for the elevation of water — Yalve pumps — Earle's steam-pump — Schabaver & 
Foures's pump for the elevation of water, sand, and gravel — Perreaux's pumps — Autody- 
namic elevators — Champsaur's — Reynolds's water jet elevator— Rotary pumps— Ceutiifugal 
pumps — Gwynne & Co.'s centrifugal pump — Xeut & Dumonfs — Coignard &. Co.'s — 
Coignard's helicoidal pump — Andrews's centrifugal pump — Girard's turbine elevator — 
Blowing machines — Lloyd's noiseless fan — Schiele's compound blowing fan — Evrard's 
rotary compression blower — Root's blower — Tuition's hydraulic pressure blower — Hydrau- 
lic presses— Chollet-Champion's hydraulic press — Desgoffd and OHivier's sterhydraulic ap- 
paratus — Apparatus for testing the tensile strength of wire — Ascenseur Edoux — Hydraulic 
counterpoise— Girard's palier glissant — Mechanical presses — pp. 169-216. 

CHAPTEE VII. 

METERS FOR LIQUIDS AXD FOR GAS-BOILER FEEDERS. 

Spirit meter of Siemens and Halske — Volumeter and alcohometer — Duboys's water meter — 
Clement's water meter — Payton's — Cochrane's meter for liquids flowing under pressure — 
Gas meters — Sugg's photometric gas-measuring apparatus — Constant level meter — Boiler 
feeders — Riedel's — Houget & Teston's. — pp. 219-236. 

CHAPTER VIII. 

MACHIXES AXD MECHAXICAL APPARATUS DESIGXED FOR SPECIAL PUR- 
POSES. 

Multiplicity of interesting objects in this class — Machinery from the United States — Sellers's 
planing machine — Machines for special purposes — Armstrong's dovetailing machine — Zim- 
mermann's— Gauze's— Whituey's gauge-lathe— Perin's band saw— Machines for making 
barrels, pencils, nails, hinges, and for dressing millstones — Brick- making machines — 
Machines for cutting tobacco, for making shoes, corsets, chenille, and for folding paper — 
Cutting sugar — Washing and corking bottles— Miscellaneous inventions— Electrical defec- 
tors— Cloth-drying— Safety brakes — Mechanical broom — Automatic grain weigher— Im- 
proved millstones. — pp. 237-280. 



CONTENTS. VII 

OHAPTEE IX. 

PROCESSES AND PRODUCTS. 

The production of steel — Paddled steel— Production of large masses by Krupp — Bessemer 
steel — Ferro-mangancse— Bessemer-steel biidge — Berard's process — Steel direct from the 
ore by Siemens's process — Artificial stone — Betoncoignet — Its applications — Ransome arti- 
ficial stone — Artificial fuel — Agglomerated coal — Material and manufacture of paper — 
Wood pulp — Cbemical treatment — Extraction of oils by sulpbide of carbon— Removal of 
oil from wool — Robert's diffusion process for sugar — Enameling and bronzing — Pleischl's 
enamels — Glaze for casks — Tucker's bronzed iron — Parkesine. — pp. 281-332. 

CHAPTER X. 

DIVING AND RESPIRATORY APPARATUS. 

Submarine armor — Antiquity of its use — The diving-bell — Diving apparatus of the New 
York Submarine Company — Diving apparatus of Ruiiquayrol and Denayrouze — Difference 
of pressure within and outside of the regulator — Form of air pump employed — Use of ap- 
paratus for cleaning bottoms of vessels — Life-saving respiratory apparatus. — pp. 332-346. 

CHAPTEE XL 

IMPROVEMENTS IN THE APPLICATION OF HEAT. 

The economical transportation of heat — Marval's heating apparatus: its application in bak- 
ing and in other industries — Siemens's regenerating gas furnace — Use of Siemens's fur- 
nace in the production of glass — Hoffman's annular brick furnace. — pp. 346-360. 



CHAPTER XII. 

ARTIFICIAL PRODUCTION OF COLD. 

General observations — Useful applications of cold — Freezing mixtures — Reduction of tem- 
perature by evaporation — Artificial production of ice— Carre's sulphuric acid freezing ap- 
paratus — Carre's ammonical freezing apparatus — Cost of ice produced in this form of 
apparatus — Carre's continuous freezing apparatus — Useful application of refrigerating ap- 
paratus — Twining's American ice machine — Economy of production of ice by Twining's 
apparatus. — pp. 361-402. 

CHAPTER XIII. 

LIGHT-HOUSE ILLUMINATION. 

Display of objects connected with the construction and operation of light-houses — Models 
of English light-houses — Use of the magneto-electrical machine — Wigham's gas-light for 
light-houses — The gas-light compared photometrically with the light from colzaoil lamps — 
The Bailey light-house— Flashing light at Wicklovv Head— Report to the board of trade 
upon the relative advantages of gas and oil for light-house illumiation — Letter to Admiral 
Shubrick — Electric light — Light as produced by battery — By magneto-electric machine — 
Regulators of electric light — The British magneto-electric machine in the Exposition — 
The French machine — Economy of the electric light — The electric light at LaHeve — Fog 
penetrating power of the electric light — Cost of maintenance at La Heve — Ladd's dynamo- 
electric machine — Magneto-electric machine of Dr. Werner Siemens — Wilde's machine — 
Experiments and apparatus of Mr. C. W. Siemens and of Professor Wheatstone — Ad- 
vantages of Ladd's machine.— pp. 403-410. 



VIII CONTENTS. 

CHAPTER XIV. 

PRINTING AND THE GRAPHIC ARTS 

Printing presses— Color printing presses — Rotary presses — Numbering presses — Dressing 
type — Printing without ink — Gilding and bronzing of characters —Stereotyping — Sweet's 
stereotype matrix machine — Flamm's typographic compositor— Composing and distribut- 
ing machines — Mitchell's machine — Graphic methods and processes— Panicography — Pyro- 
stereotypy — Lithography — Metalography — Continuous printing from engraving on metal — 
Lithographic printing rollers — Engraving — Polypantograph — Engraving by electricity — 
Dulos's method of engraving — Heliography — Photo-lithography — Photograph enamel. — 
pp. 417-468. 



THE EXACT SCIENCES. 
CHAPTER XV. 

GENERAL VIEW OF THE EXPOSITION IN CLASS TWELVE. 

Countries chiefly represented in this class — The French section — Forms of apparatus which 
are new — The American section — Model balances of the F/uited States — Barlow's plane- 
tarium — Bond's astronomical clock and chronograph — Tolles's microscope objectives — 
Wales's — Tillman's tonometer — His new chemical nomenclature. — pp. 4(39-48 1 . 

CHAPTER XVI. 

PHYSICS. 

Gravity — Densimeters — Balances — Laws of gravity — Pneumatics — Geissler's air-pump with- 
out valves — Kravogl's mercurial air-pump — Richard's multiple exhaustion — Deleuil's — 
Sound — Kcenig's exposition — Sirens — Resonators — Scheibler's tonometer — Graphic meth- 
ods in acoustics — Optical methods — Mechanical and optical methods combined — Sonorous 
flames — Heat— Thermometers — Pyrometers — Light — Optical glass — Topler's striae detec- 
tor — Polarization apparatus — Phosphorescence — Spectroscopes — Rutherfurd's solar spec- 
trum — Telescopes — Microscopes — Static electricity — Electro-static induction machines — 
Varley's — Tbpler's — Holtz's — Bertsch's — Dynamic electricity — Batteries — Ebner's — Far- 
mer's — Secchi's — Callaud's — Minotto's — Marie-Davy's — Leclanche's — Buusen's bichro- 
mate battery — Thomsen's polarization battery — Thermo-electric batteries — Farmer's — 
Marcus's — Becquerel's — Electro-magnets — Induction coils— Geissler's tubes — De la Rive's 
aurora apparatus — Meteorology — Automatic meteorological registers — Secchi's meteoro- 
graph. — pp. 462-575. 

CHAPTER XVII. 

GEODESY AND NAVIGATION. 

Method of measurement in surveying — Telemetric methods — Rochou's double refraction tel- 
escope — Lrrieux's binocular telemetric glasses — The stadimeter — Porro's steuallatie tele- 
scope — Divided object-glass telescope— Divided eye-glass telescope — Telemetric double 
telescopes — Balbreck's double telescope reflecting telemeter — Electric telemeter — Prism 
telemeter — Telemetric single telescopes — Theodolites — Dabbadie's travelling theodolite — 
Leveling instruments — Pistor and Marten's sextauts — Laurent's— Davidson's — Nautical 
compasses — Wedel-Jarlsberg's — Ritchie's — Deep-sea sounding — Trowbridge's deep-sea 
apparatus — Morse's bathometer. — pp. 576-612. 



CONTENTS. 



IX 



CHAPTER XVIII. 



METROLOGY AND MECHANICAL CALCULATION. 



Measuring rules — Dividing instruments — Catketometevs — Spherometers — Comparators — 
Micro-pantographs — Froment's — Hardy's — Peters's — Plauimeters — Oppikoffer's — Arns- 
ler*s — Laffon's — Mechanical calculation — The Arabic numerals — Counting machines — Cal- 
culating machines — Gerbert — Albertus Magnus — Roger Bacon — Napier — His rods — Loga- 
rithms — Pascal's calculating machine — Leibnitz's — Gunter's logarithmic rules — Leblond's 
Gattey's — Calculating machine of Oprandino Musina — Of Thomas de Colmar — Capa- 
bilities of this machine — Babbage's difference engine — Scheutz's — Babbage's projected 
analytic engine. — pp. 613-648. 



ADDENDA. 



Estimated value of atmospheric pressure — Thompson's rotary steam-engine — Fourneyron's 
turbine wheel. — pp. 649-650. 



LIST OF PLATES. 



Plate I. — Ericsson's Hot-air Engine— Shaw's Hot-air Engine. 
Plate II.— Belou's Hot-air Engine— Lauberau's Hot-air Engine. 
Plate III.— Otto and Langen's Gas-engine — Lenoir's Gas-engine- 
Gas-engine. 
Plate IV.— Hirn's Telodynamic Apparatus. 
Plate V. — Moerath's Wind-mill— Sterhydraulic Apparatus. 
Plate VI. — Carre's Continuous Freezing Apparatus. 
Plate VII.— Sweet's Typographic Compositor. 
Plate VIII. — Richards's Air-pump. 



-Hugon's 



11 I A 



THE INDUSTRIAL AETS. 



OHAPTEE I. 

THE RELATION OF INVENTION TO INDUSTRIAL 

PROGRESS. 

Multiplicity of machines and industrial processes at the Exposition— In- 
cessant MODIFICATIONS AND IMPROVEMENTS RESULTING FROM THE DIVISION OF 

labor — Inventions of great industrial importance are rare— Examples 
of such— The cotton-gin : its industrial, social, and political conse- 
quences—The STEAM-ENGINE, AND THE INDUSTRIAL REVOLUTIONS RESULTING 

from it— Productive power of industry limited by amount of disposable 
[ force — Handling and forging armor plates and other gigantic objects by 
the aid of steam — Precision of mechanical processes aided by steam — 
Examples of degree of refinement of mechanical accuracy — Whitworth's 
true planes and gauges— Machine tools — Influence of the steam-engine 
upon the wealth and power of Great Britain — Discovery and invention : 
their relations— Inventions directly affecting the moral and intfxlec- 
tual character of the human race — the printing press — the electric 
telegraph — different classes of inventions. 

The Commission of the United States to the Universal Exposition of 
1867, in the distribution of its labors, allotted to a committee the duty of 
reporting upon the new inventions in the useful arts presented in this 
great industrial display. The language of the resolution appointing this 
committee assigned no other limit to the field of inquiry which they 
were instructed or at least authorized to occupy, but that which was 
imposed by the extent of the Exposition itself. Whatever of novelty 
there might be found in any brauch of industry, whether in respect to 
the processes employed or to the instruments or implements used in con- 
ductiug them, would constitute apparently a legitimate subject for their 
investigation. 

This seemingly very comprehensive task was, however, essentially 
reduced by the appointment of other committees specially charged with 
the examination of large departments of industry, such as railroad engi- 
neering, steam engineering, metallurgy, the chemical arts, implements, 
machines and tools, &c, &c. ; all of which may be considered as having 
been thus withdrawn from the attention of the committee on inventions. 
The field remained nevertheless sufficiently extensive ; too extensive 
indeed to be properly explored by a few individuals, if every object pre- 
senting some feature of novelty which the Exposition embraced should 
be considered on that account to be entitled to their attention. In fact 



Z PARIS UNIVERSAL EXPOSITION. 

with such a view of their duties, they would have found their material 
exhaustless, and it would have been impossible to assign a term to their 
labors. So vast was the variety of interesting objects, and so wonderful 
the diversity of industrial operations, which a common impulse had 
swept together into that single spot from every quarter of the civilized 
world, that the visitor, in endeavoring to make his way through the maze, 
found himself continually bewildered ; and no one could leave it, after 
having devoted days and even weeks to its study, without feeling how 
imperfect had been his survey, and how inadequate a knowledge he had 
been able to gather of the great whole. 

This will be easily understood when it is considered how large was the 
area over which the Exposition was spread, and how completely filled 
and crowded was every corner of that liberal space. The palace itself 
covered nearly forty acres of ground; and the park, with the broad enclo- 
sure on the shore of the Seine, embraced about eighty acres more. To this 
must be added the fifty acres of the island of Billancourt. In many por- 
tions of the palace the objects on exhibition were too numerous for the 
space allotted to the exposants, and permission had been sought and 
obtained to occupy with the more bulky, or the more showy the ? space 
in the avenues and passages, to such an extent as considerably to 
obstruct circulation. The number of exhibitors exceeded fifty thousand. 
A visitor who should have desired to distribute his attention impartially 
among all these candidates for his approbation, would scarcely have 
been able to give to each more than the most cursory glance. The gates 
were opened every morning at eight o'clock and closed every evening at 
six. By giving a single minute to each exhibitor, and by employing 
faithfully all the intervening time, it would have been possible to dispose 
of six hundred in a day. But even at that rapid rate, it would have taken 
three months of unintermitted labor to complete the list. Many of these 
exhibitors, moreover, presented not single objects, but scores and hun- 
dreds. There is no extravagance at all in the assertion that the num- 
ber of objects in the Exposition, each individually interesting and worthy. 
if time allowed, of a separate examination, amounted to several millions. 
In such a scene the attractions and the distractions are so equally bal- 
anced, that it is only after the observer has resigned himself to the 
necessity of passing by the greater number without an attempt at a 
critical notice, that he is prepared to form an intelligent judgment of 
those that remain. 

If, again, in the study of such a multiplicity of industrial processes or 
machines, he endeavors to make a distinction between what is justly 
entitled to be called original and what is familiar and common, he finds 
himself arrested by a new embarrassment. There is no form of industry 
which, in our day, is stationary for a moment. There is none which is 
not undergoing improvement so incessant that even while the history of 
the most recent advances is being written, they are beginning already to 
be numbered with the past, and giving place to improvements newer 



DIVISION OF LABOR STIMULATES INVENTION, 3 

still. This is peculiarly the case in those great branches of industry 
which require for their successful prosecution the concentration of capital 
and the systematic division of labor. The division of labor is a practi- 
cal analysis of the industrial problem into its most elementary parts ; 
and the distribution of these parts to as many individuals brings the 
force of many minds or groups of minds to the study of the question of 
improvement under the most advantageous conditions. It is true that 
many workmen pursue their daily task in a manner entirely mechanical, 
without considering whether or not it might be accomplished in a better or 
a simpler way ; but it is also true that the most useful modifications of 
many industrial processes and machines have been the suggestions of the 
men employed in using them, and have been the fruit of their personal 
experience and observation. It is further true that in large industrial 
establishments there exists always a facility for testing the advantages 
offered by a newly suggested implement or process, which does not exist 
elsewhere ; and that therefore a new invention, if brought forward in 
such a field, will not have long to wait, that its merit, if it has any, may 
be recognized. And thus it happens that in such establishments rarely 
a day, and certainly never a year passes, in which successful ingenuity 
does not make some addition to productive power, by giving to its instru- 
ments increased efficiency, or to its products a superior quality. 

Such being the case, there cannot be a great industrial congress, like 
that assembled in the Exposition of 1867, which will not be full of what 
may in one sense be called new inventions; but of these the great 
majority will have for their basis some industrial process or machine 
which is not new, but is common to the entire branch of industry to 
which they belong. The textile arts, for example, employ a larger vari 
ety of machinery than any other, or, at least, than any other whose pro- 
cesses are capable of being fully exhibited in a place like the Exposition 
and under the eye of the public ; yet, it may be said, generally, that the 
processes by which fibrous materials are prepared for the spindle or the 
loom are substantially the same now in kind and in order as they were 
in the earliest period of history, and when the art was in its most rudi- 
mentary condition. But the modes and instrumentalities by which 
these changes are produced have been so completely transformed that 
in its present condition the art would be totally unrecognizable by one 
who had known it only under the slow forms practiced by the Eomans 
or the Egyptians. These transformations have been the offspring of a 
few great inventions, of which each in its time has marked an era in the 
history of this industry. But it is in the nature of great inventions that 
they narrow the field of activity to future ingenuity ; and that while 
they may admit of subordinate modifications and improvements, they 
are but tardily, if ever, dethroned by successful rivals. Much the larger 
number, therefore, of the novelties in industrial art which each year 
introduces consists of these minor improvements; and to make an 
exhaustive enumeration of such, as they appear in a general exposition 



4 PARIS UNIVERSAL EXPOSITION. 

of the industries of the world, would involve the necessity of descending 
to an endless minuteness of detail. An observant visitor to the gallery 
of the Exposition devoted to the useful arts, who should have carefully 
compared, for instance, the various machines in use for the manufacture 
of cotton, would have noticed that, while each exhibitor employed for 
the same operation substantially the same mechanical contrivance, yet 
nearly every one also claimed some peculiarity in the details of construc- 
tion as original with himself. The observer would have, perhaps, been 
still more forcibly impressed with the evidence of this truth in looking 
through the magnificent collection of objects which modern ingenuity 
has so wonderfully multiplied, under the name of machine tools. The 
differences might strike him as larger than in the former case, but he 
would still observe the same general form and substantially the same 
modes of operation, though with many variations in the manner and 
succession of movements and in the relative position of the tool and the 
material operated upon. Another illustration might be found in the 
important art of printing. Since the origin of this art in the memorable 
invention by which impressions were first taken from movable type, its 
history has been marked by a number of transformations in the mechan- 
ical part of the process so signal as to form each for itself a new era. 
One of these was the introduction of the power press and the substitu- 
tion of the cylinder for the platen, and another was the transference of 
the form from the horizontal bed to the cylinder and the suppression of 
the reciprocating motion. By each of these improvements there was 
effected almost as large an advance in the power of multiplying impres- 
sions beyond what had been before possible as had been attained by the 
original press of Gutenberg over the slow process of transcription. But 
in the intervals between these great steps of advancement the printing 
press underwent innumerable minor alterations and improvements, many 
of which tended greatly to increase its efficiency and to improve the 
excellence of its work without, nevertheless, changing its essential char- 
acter or making of it a new, although they made it a better, machine. In 
the recent and familiar invention of machine-sewing we have still another 
exemplification of the same distinction. The germ idea successfully 
embodied in the original machine was one of immense value ; the numer- 
ous modifications which the mechanism has since undergone — every 
detail having been made the subject of half a dozen patents at least — 
have had a value only relative and secondary. And though in some 
instances the ingenuity of inventors has devised mechanical combina- 
tions essentially original for performing the same work, the success. 
however mechanically interesting, is without striking industrial impor- 
tance, since it accomplishes no new result. 

If we attend to the current history of invention we shall observe that 
much the larger number of the contributions to industrial advancement 
which present themselves in the form of new processes in the arts or new 
adaptations of mechanical principles to manufacture are of the secondary 



Whitney's cotton gin. 5 

and relatively unimportant class above distinguished. But what each 
single invention may lack in its separate importance is amply compen- 
sated by the combined value of the immense number which are continu- 
ally and simultaneously originating. The general growth of productive 
industry in the world is, consequently, nearly uniform and steady. At 
distant intervals there may occur a sudden swell in the wave, in conse- 
quence of the appearance of one of those rare inventions which are des- 
tined to give to some great branch of industry an entirely new character, 
or whose stimulating influence makes itself felt throughout all industries ; 
but the current never sets backward, and whatever is gained from each 
of these extraordinary impulses remains a permanent acquisition. 

To illustrate by example the nature of these occasional and singular 
impulses, we may refer to the consequences which have followed from 
the invention of the cotton gin. So long as no better mode had been 
thought of, of separating the seed of the cotton-plant from its accompa- 
nying fibre, but that of picking out each seed by hand, there existed a 
natural and entirely effectual obstacle in the way of making this valua- 
ble material the basis of a great manufacture. Whatever might be' the 
demand, there was a physical limit to the supply. There can, of course, 
be no doubt that it was the demand which enlisted ingenuity in the 
endeavor to overcome the obstacle, and to make an increase of the sup- 
ply a possibility. It was, therefore, the demand which produced the 
machine. And it is, accordingly, no injustice to the ingenious inventor 
to whom we owe it, meritorious as we admit him to have been, to say 
that had he not turned his thoughts in this direction, nor devised this 
particular mechanical contrivance for performing a work of which the 
world had so pressing need, some machine, in all material respects, 
equivalent to this, must have made its appearance without any long 
delay. Of the many minds then directed toward the solution of a prob- 
lem of so vast importance, though none, indeed, yet perceived how vast, 
some one, or perhaps more than one, must have resolved it successfully, 
had not the opportunity been taken away. 

But if it is correct to say, on the one hand, that the demand produced 
the machine, it is no less true, on the other, that the machine stimulated 
the demand to a most extraordinary degree. From the insignificant 
amount of 150,000 pounds of American cotton received in England in 
1791, the exportation to that country rose in ten years to 15,000,000. At 
the same time, the practically unlimited extent of soil adapted to this 
culture on the American continent made it evident that the demand might 
grow to any extent without producing a corresponding increase of price, or 
even with an actual reduction. Such a supply of a material capable of 
being wrought into the largest variety of textile fabrics could not but 
stimulate the introduction of numerous and signal improvements into all 
the processes of manufacture. Thus the creation of the automatic 
machinery by which the production of cotton fabrics, early within this 
century, rose to a hundred-fold what it had been at the close of the last, 



6 PARIS UNIVERSAL EXPOSITION. 

and by which, in the year 1860, it had been brought to a thousand-fold 
at least, was a direct consequence of the invention of the cotton gin. 
Nor was the influence of this invention confined exclusively to matters 
of industrial or economical importance. It affected profoundly the social 
condition of multitudes in both hemispheres, and in one of them involved 
very grave political consequences. But for the increased and constantly 
increasing importance of cotton to the industry of the world, those of 
the American States which were fitted by soil and climate to the pro- 
duction of this plant would not have neglected every other industry 
in the pursuit of this alone, nor have become rooted in the belief that 
compulsory labor was essential to their prosperity. And had it not been 
for this belief, and for the discordance of views which grew out of it 
between the cotton-producing States and the other members of the 
American Union upon matters, both political and moral, of vital impor- 
tance, the terrible convulsion which has recently shaken the Union to 
its centre could never have occurred. It is at once curious and inter- 
esting to trace a connection between two events so widely different in 
character and so widely separated in time as the great rebellion of 
1861 and the invention of the*cotton gin ; yet, from what has just been 
said, it is obviously admissible to regard these two events as stand- 
ing to each other in a certain sense in the relation of cause and con- 
sequence; and though the great national disaster just mentioned may 
have been immediately precipitated by causes much less far to seek 
and much more easily recognizable, still, at the distance of two-thirds 
of a century, the connection just hinted at is to the eye of the political 
philosopher not the less clearly discernible. In this proposition it is 
not intended to assert that the rebellion would not have occurred if 
the invention had not been made. It has been remarked already that 
the time had arrived in the world's history when the cotton industry, 
in obedience to the law of industrial advancement — a law as constrain- 
ing as that of organic development — was destined to receive a large 
expansion. If the machine which, in point of fact, was instrumental 
to the fulfilment of this destiny had not presented itself, some equiv- 
alent form of mechanism must have done so ; so that the way would 
have been opened for the entrance of a train of moral and political con- 
sequences in all essential respects resembling those which it has been 
our misfortune to witness. It would be wrong on this account to infer 
that any great industrial improvement, whatever the temporary or local 
evils of which it may be the occasion, can ever be a real calamity to the 
human race. The remarks here made are intended only to illustrate the 
degree to which a single invention may often influence the destinies of 
nations. Whether this influence shall be wholly good or wholly or par- 
tially evil will often depend upon the pre-existing state of human society. 
in the midst of which the invention has its birth. To the world the 
benefit which has resulted from the vast development which the cotton 
manufacture has received within the present century is great beyond 



THE STEAM-ENGINE 7 

the power of calculation ; to a portion of the world, long more than 
equally a sharer in the benefit, it has proved for the time a source of bit- 
ter evil. If in making up the account we have to consider both results, 
it is due to the cause to credit it with all the benefit as its proper and 
legitimate offspring, while the evil must be charged to the unnatural 
condition of society which this cause only tended to perpetuate. 

The industrial revolution which followed the invention of the cotton- 
gin was confined to a single, though an extremely important, branch of 
industry. In some rare instances an invention has appeared whose 
wider relations to the means of production have extended its influence 
to many industries, at once, and even ultimately to all industries. Such 
an example presents itself in the case of the steam-engine. Before the 
introduction of this machine, all heavy industrial operations were effected 
by the muscular force of men or animals, aided, where circumstances 
permitted, by the power of running streams. The winds were laid under 
contribution for certain lighter industrial tasks ; but it needs very little 
reflection to perceive how limited must have been and must always be 
the range of their usefulness. The productive power of any industry 
must always be limited by the amount of force disposable for its pur- 
poses. While the only considerable force, except that of animals, at the 
disposal of man was the force furnished by falling water, it is obvious 
that all great industrial operations were confined of necessity to certain 
localities. No great factories, no great foundries or rolling mills for iron, 
no great flouring-mills for grain, could exist except in those rugged dis- 
tricts through Avhich the mountain torrents make their way to the low- 
lands or the ocean. The broad and level tracts which form so vast a 
proportion of the habitable continents, and which by their fertility are 
adapted to sustain the densest population, could have no part in these 
great industries. Nor was it a slight inconvenience that, as a general 
rule, the power and the material on which it was to operate were not to 
be found on the same spot. As the power did not admit of transporta- 
tion, it was necessary to carry the material to it; a necessity involving 
much loss of time and labor, and no slight expense. The transportation 
to great distances of raw material, though in the existing state of many 
industries it is often necessary, is attended with great and obvious dis- 
advantages which it is desirable to avoid. The part of this material 
which becomes ultimately utilized in the manufacture, constitutes in 
many cases but a small proportion of the entire weight, and perhaps a 
less proportion still of the bulk; so that the greater portion of the 
expense of transportation is paid for the moving of substances which are 
not only useless, but which must be got rid of before the remainder can 
be useful. These are disadvantages under which all grand industries- 
labored while dependent upon water-power alone. Nor were these all, 
for it is probable that in some branches, at least, they could never have 
reached their present development, had they continued to be always SO; 
dependent. For the highest uses of industry, it is not enough to have 



8 PARIS UNIVERSAL EXPOSITION. 

at command a great amount of power ; it is also indispensable to be able 
to concentrate it upon occasion within small space. In the British 
and French departments at the Exposition may be seen armor-plates for 
ships originally rolled from twenty to thirty feet in length, from three to 
six feet in breadth and from eight to thirteen inches in thickness. The 
force required to drive these masses through the rollers from which they 
receive their form, could hardly be conveniently obtained from a water- 
power. Moreover, the massive hammers now required to forge the huge 
masses from which these plates and other gigantic objects are formed 
would be wholly unmanageable without the use of steam. 1 

The steam-engine not only does the work of water equally well, but it 
does it equally well under every variety of circumstances. It furnishes 
power in any amount that may be required, and in any place. If a raw 
material is to be manufactured, the power may be set up where the 
material is produced. Place it in the forest and it will reduce the trees 
to the form of lumber for the market ; or, if more is exacted of it, will 
mould them to finished forms ready to be united by the cabinet-maker or 

1 While the Exposition was still in progress, Sir John Brown, of the Atlas Iron "Works, 
Sheffield, England, caused to be rolled a plate surpassing in dimensions even the largest of 
the immense masses above spoken of; its length being twenty feet, its breadth four feet, and 
its thickness fifteen inches. Even this extraordinary achievement by no means exhausts the 
power of the mills or the capacity of the furnaces; but plates are rolled no larger, only 
because larger plates have not been demanded, and because no floating battery could carry 
them. The scene presented in the Atlas works, at the time of the rolling of this huge plate, 
is vividly described by a correspondent of the London Times who was present on the occa- 
sion. It is quoted as furnishing a most striking illustration of the extraordinary change 
which the steam-engine has wrought in the most important of the world's industries : 

"The plate was not quite ready at the time appointed, and during the short interval of 
delay the works were inspected. It is almost impossible to describe the aspect of cyclopean 
activity which they presented The huge space of lofty workshops, covering more than 23 
acres of ground, were, above, all dim with smoke ; below, all dazzling with the blinding 
glare and heat of furnaces. Everywhere ponderous fly-wheels were spinning round with a 
loud hum through the gloom, everywhere steam-hammers were falling with a shock upon 
the solid earth that made the walls vibrate, and people near them jump under the tremendous 
concussion. No place seemed free from steam or flame or melted iron. The dark nooks 
would suddenly become bright, as furnace doors were lifted and emitted their long light- 
looking flames of dazzling white vapor, and disgorged a mass of seething metal, which 
men, almost clad in light steel armor, wheeled away and shot under the steam-hammers, the 
first stroke of which sent jets of melted iron rushing in trains of fire like meteors in all 
directions. Sometimes one came on groups of men who were saturating in water the rough 
bands of sacking in which they were enveloped before going to wrestle with some white- 
heat forging, sometimes on men nearly naked, with the perspiration pouring from them, 
who had come to rest for a moment from the puddling furnaces, and to take a long drink of 
the thick oatmeal and water, which is all that they venture on during their labor, and which 
long experience has proved to be the most sustaining of all drinks under the tremendous 
heats to which they are subjected. On every side the glare, the smoke, the din, and steam 
are alike deafening and blinding. On every side are masses of melted iron running down 
troughs, or great blocks of it heated to a glow that is almost melting being welded and 
knocked away in myriads of sparks and jets of refuse under the blows of the hammers- 
Most uncomfortable of all are the slabs of armor-plate and blocks of steel ingots which, half 
cooled, and of a dull slate color, lie about everywhere. From those in a bright, red glow, 
the visitor can guard himself, for he sees them ; but from those which are partly cooled, but 



THE STEAM-ENGINE. \) 

the joiner. Place it by the side of a quarry, and it will convert the rude 
blocks of marble disengaged by the workmen to geometrical shapes, suita- 
ble to be laid in the walls or to adorn the interior of a palace. In the min- 
eral region it offers its services to the metallurgist in every branch of his 
difficult labor. It blows for him the bellows, it lifts the heavy hammer, 
it turns the powerful lathe, it drives the steady tool of the plane, it 
crushes between resistless jaws the fiery masses which are to form the 
iron ways of our railroads, or the ponderous walls of our floating bat- 
teries. In a country favorable to the textile arts, it performs with incred- 
ible rapidity and facility all those operations which for so many centu- 
ries were accomplished by the slow and painful labor of human hands, 
separating the useful fibre from its impurities, loosening its entangle- 
ments, preparing it for the spindle, drawing it out into threads, and 
finally weaving it into fabrics of endless variety and beauty ; performing, 
also, all this work equally well upon a hundred looms at once, or upon 
a single one. 
Besides this, the steam-engine presents itself as a ready helper in all 

yet hot enough to scorch the flesh from the bones when closely approached, there is little 
safeguard, as one hurries out of the way of seething puddle blooms or open furnaces, which 
diffuse such an intense general heat around that little extra warning is given by the treach- 
erous masses of half-cooled slabs till the danger is almost too near to be avoided. After seeing 
and suffering under seeing such scenes, the visitors were conducted to the armor rolling-mill, 
where the monster plate was to be drawn. The process of drawing it is simple, but peculiar. 
The plate, when laid in the furnace, rests upon little stacks of fire-bricks, so that the flame 
and heat plays equally round it, till all is glowing white, and the successive layers have 
settled down into one dense mass. A great deal of the success depends upon the time at which 
the plate is drawn and the amount and length of time to which it is to be heated. All this is 
regulated by the chief roller and chief furnace-man, who are paid wages which many emi- 
nent professional men might envy — wages amounting from 1200L to sometimes 2000Z. a 
year. On Friday, as the time for ' drawing' approached, these officials opened the furnace 
doors, and, approaching close to them with only the shelter of a lump of wet rag held loosely 
before their arms and faces, peered into the blinding glare from time to time with as much 
care and apparently as much indifference as if they were looking into the tube of a telescope. 
Suddenly, at a signal from the furnace-man, the bands of workmen, to the number of about 
60, arranged themselves on each side of the furnace, as near to it as they could bear the 
heat. Then the doors were opened to their fullest, and what had been a glare before and 
what had been a heat were quite eclipsed by the intense light and fervency with which the 
long tongues of flame leapt forth. In the midst of this great light lay a mass even whiter 
than the rest. To this some half a dozen men drew near. They were all attired in thin 
steel leggings, aprons of steel, and a thin curtain of steel wirework dropping over their faces 
like a large, long visor. All the rest of their bodies were muffled in thick wet sacking. Thus 
protected they managed, with the aid of a gigantic pair of forceps slung from a crane above, 
to work as it were amid the flames for a few seconds, and to nip the huge plate with the 
forceps. The signal was then given, and the whole mass of iron, fizzing, sparkling and 
shooting out jets of lambent flame, was by the main force of chains attached to the steam 
rollers drawn forth from the furnace on to a long wrought-iron car. The heat and light 
which it then diffused were almost unbearable in any part of the huge mill, but the men 
seemed to vie with each other to approach and detach the colossal pincers which had 
drawn the iron forth. More than a dozen attempts were made on Friday before this was 
effected, and more than a dozen of the best and most skilful workmen were driven back one 
after another by the tremendous heat and glare. At last all was made clear. The forceps, 
then red-hot from their grip of the plate, were drawn away, the chains cleared from the rollers, 



10 PARIS UNIVERSAL EXPOSITION. 

the minor industries, which, until its introduction, had no resource but 
that which was afforded them in animal power. The turner, the wheel- 
wright, the carpenter, the joiner, the locksmith, the brass-founder, the 
lapidary, the printer, the optician, the confectioner, the baker, the agri- 
culturist, may now accomplish the most laborious part of their several 
tasks, with only the personal exertion on their own part which is neces- 
sary to superintend, and, from time to time, to guide the work of the 
tireless assistant which they find in the steam-engine. In agriculture 
the advantage which the engine is capable of affording is but recently 
beginning to be realized, but already its use is all but universal in Eng- 
land, and is becoming general in our own country, in threshing out the 
grain crop ; and it is beginning to be successfully employed in driving 
the plough and the cultivator. A single English engine-building house 
sold, in 1852, two hundred and forty-three portable engines for farms, 
representing a horse power of 1349 ; in 1862 the number was more than 
doubled, and the horse-power increased threefold. 

and, with a great hurrah, the other workmen seized the chains attached to the iron truck, 
and drew it to the incline by main force, where it was left by its own weight to run into the 
jaws of the rolling-mill. It was then sauve qui peut among the workmen, who rushed for 
shelter in all directions as the mass was nipped between the rollers, and wound rapidly in 
amid quick reports like those of dull musketry, as the melted iron was squeezed by the 
tremendous pressure out of the mass, and flew out in jets of liquid fire on all sides. In spite 
of all the care and all the skill which the best workmen can use on these occasions, they 
cannot always escape the splashes of melted iron, and the burns inflicted are numerous and 
often severe. The turning of the rollers crushes the plate through to the other side, where 
it rests for a minute on a wrought-iron truck similar to that on which it was brought from 
the furnace. The action' of the rollers is then reversed after they have been by the action of 
screw levers brought closer together by about an inch. These again nip the plate and drag 
it back in an opposite direction, and again and again does the mass go forward and back- 
wards, each time passing between a smaller space between the rollers, till, as on Friday, the 
whole of the huge thickness was reduced to a compact mass 15 inches thick, in less than a 
quarter of an hour. During every stage of the process, quantities of fine sand are thrown 
upon the plate, and this literally takes fire as it touches the flaming surface, and covers it as 
it melts with a coat of silica, or with a glaze like that of earthenware. After every discharge 
of sand, and these go on almost incessantly, buckets of water are thrown upon the plate and 
explode in clouds of scalding steam, and when these are partly dissipated men rush forward, 
and with w r et besoms with handles 20 feet long sweep off whatever little scraps of oxidation 
may have taken place. Thus every time the plate passes through the mill the sand is scat- 
tered, the water thrown, and the surface swept, and at every roll the chief roller of the estab- 
lishment runs forward, and, under the shelter of wet cloths, measures with a gauge its 
thickness from end to end. On Friday the required dimensions were obtained, as we have 
said, by less than a quarter of an hour's rolling, and a plate 15 inches thick, the product of 
the labor of nearly 200 men and of the consumption of nearly 250 tons of coal, was shot out 
by the rolling-mills and left to cool. When this had been effected two large rollers of iron, 
each weighing 15 tons, were placed upon it by the cranes, and moved slowly backwards 
and forwards, and, eventually, as the plate cooled, were left upon its ends to keep the whole 
perfectly level. Nothing further now remained in order to complete it as the finest specimen 
of armor-plate manufacture ever attempted but to plane off its rough ends and edges. The 
flat surfaces on either side, which form what is called the skin of the plate, are never interfered 
with, for the action of the steel rollers leaves them literally almost as smooth as plate g'.ass." 



MACHINE TOOLS. 11 

Another industrial revolution, no less important than those already 
mentioned, has resulted from the invention of the steam-engine. With 
the advancement of mechanical art, precision in the execution of its pro- 
cesses becomes a requisite more and more indispensable. In the earlier 
period of the history of industry, and even until a time comparatively 
recent, no higher precision was obtainable than that of which the human 
hand is capable; and this could be secured only through the trained 
skill of the most accomplished artisans. Moreover, in proportion as the 
dimensions of the work to be executed were larger, or the weight of the 
mass to be operated on more considerable, the difficulties of the task 
were proportionally increased ; so that a practical limit to accuracy was 
very soon reached. The state of the mechanic arts in this respect at the 
time of Watt's invention is well illustrated by the historical fact that, 
for more than ten years, owing to the impossibility of constructing a 
piston and cylinder steam-tight, the conception of the engine could not 
be realized in practice. This difficulty had nearly disheartened the 
inventor and ruined his associates, when, at length, Mr. Boulton, a cap- 
italist, but, happily, also a metallurgist and engineer, entitled by his 
ingenuity, energy, and practical skill to be distinguished as the Whit- 
worth of his day, came to his relief, and by means of the exceptional 
superiority of workmanship to which he had attained in his celebrated 
establishment at Soho, saved to the world the most valuable invention 
which had ever then been offered to its acceptance. And yet, though the 
invention was at last successful, it was but barely so. The earlier engines 
produced by Watt and Boulton would be regarded at this time as 
but little better than monsters of rudeness. 

But the engine having succeeded, and having relieved the mechanical 
artisan of the drudgery attending his task, became presently an instru- 
ment of improving most remarkably the quality of his work. It was 
soon perceived that an iron arm could direct a tool with a precision which 
the most practised human skill could never attain. The class of mechan- 
ical contrivances called machine tools came into existence ; and, in the 
manufacturing world at least, the file, the plane, the chisel, the auger, 
and the drill in the hand of man, except for the most trivial and unim- 
portant purposes, entirely disappeared. With this change, also, there 
ceased to be a limit to the improvement of mechanical art, short of abso- 
lute perfection. Accuracy of workmanship has now reached a point at 
which the gradations of difference in dimension which it is perfectly in 
the power of the workman to give to an object on which he is employed, 
are entirely too minute to be perceptible, except by the aid of powerfully 
magnifying helps. A remarkable illustration of the fact here stated is 
furnished by Mr. Whitworth in a little contrivance for measuring, or 
rather for comparing, lengths, which is exposed by him in the annex in 
which his heavy guns are exhibited. This apparatus is designed to test 
the truth of a solid measure representing in length an English inch. It 
embraces, as exhibited, the standard inch with which the new one is to 



12 PARIS UNIVERSAL EXPOSITION. 

be compared. This solid has the form of a rectangular prism, originally 
nearly or quite cubical. It is formed of polished steel. Its extreme edges 
have been truncated at angles of forty-five degrees, so as to reduce the 
terminal surfaces to the dimensions of about a quarter of an inch square. 
The lateral edges are also rounded, in order to facilitate the manipula- 
tion. It rests on a rectangular trough, of which the sides are equally 
inclined to the horizontal. At one of its extremities it abuts against a 
fixed stop, which is provided with the means of the necessary adjust- 
ment. The other is opposed to the extremity of a screw of twenty threads 
to the inch, placed directly in the line of the axis. A single revolution 
of the screw advances the extremity, therefore, one-twentieth of an inch. 
But the head of the screw is ten inches in circumference, and is divided 
into 200 parts. In turning this wheel, every division accordingly advances 
the screw one four- thousandth part of an inch. The divisions, however, 
are not traces, but teeth ; and the screw-head is a gear-wheel, which is 
driven by a tangent screw lying horizontally in its plane and across its 
summit. And this tangent screw has also a head of 12J inches in cir- 
cumference, which is divided into 250 parts, each part being the twen- 
tieth of an inch. An entire revolution of the tangent screw advances 
the gear wheel only one tooth, which, as we have seen, moves forward 
the end of the measuring screw one four-thousandth of an inch. A sin- 
gle division of the limb of the tangent screw-head will therefore produce 
a movement in the direction of measurement of only one two-hundred- 
and-fiftieth of one four- thousandth of an inch — that is to say, of one one- 
millionth part of an inch ; and to this degree of refinement it is Mr. 
Whitworth's belief that mechanical accuracy can be practically carried. 
It might be said in objection, that while there is no fault to find with 
the correctness of the mathematical conclusion deduced from the known 
relations of the parts of this instrument, yet from the possible flexure or 
compression, or slight imperfection in the fitting of parts, there is room 
for error to the extent certainly of so minute a fraction as one one-mil- 
lionth part of an inch ; a fraction so minute that not only the senses fail 
to detect, but the mind is even incapable of conceiving it. Mr. Whit- 
worth has anticipated this objection, and has met it by a practical and 
very ingenious answer. Between the plane face of the standard inch and 
the extremity of the measuring screw opposed to it, he has introduced a 
little steel plate with parallel and perfectly true surfaces, from the two oppo- 
site ends of which, for convenience of manipulation, there extend two 
slight arms in the direction of its plane. Before the measurement is 
begun the screw head is turned far backward, and this plate lies loosely 
between the screw and the standard, with its plane vertical, being sus- 
tained in this position by its arms, which rest on supports on each side. 
As the screw advances in the operation of measurement, the plate has 
less and less freedom of space, until at length it appears to be in actual 
contact with both screw and standard. But that this appearance is 
deceptive, is easily demonstrated by raising the plate slightly by moans 



whitworth's micrometric apparatus. 13 

of one of its handles, when, on being released, it will fall freely back, 
showing that it is not yet impeded by friction. If, now, the tangent 
screw be turned, a single division at a time, lifting the plate after each 
movement, a point will be reached at which, from perfect freedom, a sin- 
gle additional division of advance will fasten the plate completely, so 
that when lifted it will be held by friction at the point where it is placed, 
and will no longer fall. Between these two positions the screw has 
advanced one one-millionth of an iuch ; and the certainty that this is a 
real and not an ideal accuracy of measurement is proved by the fact that 
the operation may be repeated, and that, provided care be taken to gnard 
against disturbance of the equilibrium of temperature, the arrest of the 
plate will continue to occur between the same two divisions of the screw- 
head. 

Other illustrations of the exceeding mechanical accuracy which has 
been reached by the same ingenious exhibitor, may be found in the " true 
planes" and the gauges, of which an extended series has been presented 
by him in the Exposition. The gauges are perforated steel plates, the 
perforations being highly polished within, and differing from each other 
in diameter by one ten- thousandth of an inch. Corresponding to them are 
polished steel cylinders, one exactly fitted to each. As these cylinders 
lie side by side, it would be difficult for the eye to distinguish a differ- 
ence of diameter between several of them ; but when they are tried by 
the gauges, the difference is directly detected, since while each will pass 
freely through the aperture corresponding to its own number, no one can 
be forced without an effort into one of a higher order. The " true planes " 
are polished metallic surfaces of about one hundred square inches each. A 
pair of them are exhibited resting one on the other. They have a thick- 
ness of about half an inch, but are stiffened by means of deep ribs cast 
upon the reverse, which ribs connect the points, three in number, on which 
the plate is intended to rest when placed face upward. These plates 
nowhere deviate from true geometrical planes by an error exceeding the 
one one-millionth part of an inch. In the process of their construction 
they are ground one upon the other 5 but as by this means they might 
become truly adapted to each other without being necessarily truly plane, 
they are always constructed in triplets instead of pairs, the third plane 
serving to verify the other two. Indeed it is obvious that if, of two sur- 
faces truly fitting each other, one should be convex and the other con- 
cave, a third could not possibly fit both. And only on the supposition 
that all three should be truly plane, could any two out of the three, 
chosen indifferently, fit equally well. 

Of the two planes exhibited, when one is lifted and replaced upon the 
other, by a movement at right angles to its surface, it glides over the 
inferior plate more smoothly than if it were resting upon ice. This is 
because there is included between the two a cushion of air, which, how- 
ever thin, serves to reduce, or as it might be said to annihilate, friction 
more effectually than could be done by any known lubricant. When, by 



14 PARIS UNIVERSAL EXPOSITION. 

pressure and by sliding the plate to and fro, this cushion is pretty thor- 
oughly expelled, the plates adhere so strongly that the upper will easily 
lift the lower by the effect of external atmospheric pressure, and would 
probably lift it though its weight were very much greater. 

The extreme mechanical accuracy which the examples above described 
serve to illustrate, has been a consequence of the introduction into 
mechanical art of machine tools ; and machine tools have owed chiefly 
their invention to the steam-engine. But it is not merely in respect to 
artistic excellence that the products of manufacturing industry have been 
improved by the improved methods of production ; this improvement is 
attended also with a great economical advantage, resulting from the 
entire similarity of form and dimensions which distinguishes all the 
objects produced by the same process. When the hammer, the chisel, 
the rile, the drill, in the hands of a man, were the only means of producing 
the various implements, machines, vehicles, and other constructions 
necessary for the daily uses of the farm, the family, or the workshop of 
the petty artisan, if a part became unserviceable it could not be immedi- 
ately replaced, and possibly the whole machine became a loss. In modern 
manufacturing industry, no part of a construction is made for a particu- 
lar machine, but what will serve for one will equally well serve for any 
other. A fracture of a wheel, or a lever, or a pinion, involves therefore 
but a momentary inconvenience. The loss is directly made good, and 
the machine moves once more. 

But the steam-engine has not only increased the accuracy of con- 
structive art ; it has also greatly extended its power. Undertakings of a 
magnitude which could not have been attempted, and which would pro- 
bably not have been thought of without it, have become by its aid oper- 
ations of daily accomplishment, and are too familiar to attract especial 
notice. A mass of thirty or forty tons of metal is now wrought upon all its 
surfaces and transformed into any desired shape with greater facility and 
in vastly less time than would have been required at the beginning of 
this century to deal with half as many hundreds. This truth is illus- 
trated in the immense ocean steamer crank-shaft exhibited by Mr. Knrpp, 
wrought to its present difficult form, with elbows at right angles to each 
other, from a mass of twenty- seven tons, which in the operation has become 
reduced to fifteen; or the similar shaft exhibited by Messrs. Petin & Gaudet, 
of France ; or the fifty-ton steel gun of the first-named exhibitor, and the 
twenty-five-ton gun from Woolwich: and the equally ponderous artillery 
shown by Mr. Whit worth, and by the government of France. To these illus- 
trations may be added all the magnificent and splendidly finished forg- 
ing s of the marine engines exhibited by the Creuzot works in Their annex 
and on the Berge, to say nothing of the massive frames and bed-plates 
of the great machine tools themselves, the planing machines especially. 
exhibited by Whitworth of England, Sellers of the United States. Maze- 
line of France, and many others. 

There remains to be mentioned one additional and most important 



POLITICAL CONSEQUENCES OF WATT'S INVENTION. 15 

consequence of the invention of the steam-engine, which has impressed 
profoundly not merely the industrial but the political history of the 
world. If the cotton-gin has been for much in controlling the political 
and social destinies of the western continent, the steam-engine has been 
for still more in fixing for England her place among the nations of the 
earth. At the time when this splendid invention made its appearance, 
England called herself mistress of the seas, and assumed to be the equal, 
if not the superior, of any military power upon the land. This place she 
still claims, perhaps justly, though her title to the exclusive dominion of 
the waves can no longer pass unchallenged. But without the steam- 
engine, the power of England would have long since suffered a hopeless 
paralysis. It is from the depths of her mines that she has drawn the ali- 
ment which has sustained her manufactures and fed her boundless com- 
merce and built up the enormous wealth which is the basis of her j)resent 
strength. Her iron and her coal have made her a hundred times richer 
than she could possibly have been if she had possessed instead of them 
all the gold of California and all the diamonds of Brazil. But a century 
ago, just as Watt was turning over in his mind his first crude notions of 
the motor which was destined to transform the constructive industry of 
the world, many a thoughtful patriot and statesman of Great Britain 
must have been regarding with anxiety and alarm the stagnation which 
seemed to be gradually creeping over the mining industry of his country, 
and the danger which menaced with speedy total extinction this great 
source of her national wealth. As the mines were sunken deeper, the 
expense of lifting to the surface- the mineral extracted, of course increased ; 
but this was a trifling consideration compared with the vastly greater 
expense of withdrawing the water which flowed in, in constantly increas- 
ing abundance, and which had to be raised from a constantly increasing 
depth. In many instances mining had almost ceased to be remunera- 
tive ; in many others quite. One after another the mines were abandoned 
and the water was allowed to fill them up. What had already happened 
in many instances could not fail to happen at length in all. An early ruin 
plainly impended over the mining industry of Great Britain, which could 
not fail to bring with it, and with the consequent failure of her fuel, an 
equal ruin to the manufactures, the commerce, the wealth and the politi- 
cal power of the British empire. 

It was at this critical juncture that the new motor appeared. For 
some time after its appearance, it was only for the drainage of mines 
that its immense powers of usefulness seem to have been recognized. 
So imperfect at that time was the state of advancement of the mechanic 
arts ! But applied to this purpose, then of paramount importance, it 
averted at once the imminent danger which menaced British industry, 
and restored to Britain the commercial sceptre just as it was about to 
fall from her grasp. The greatness of the British empire to-day is, 
therefore, clearly due to her early possession of the steam-engine. With- 
out it she must inevitably and speedily have sunk to a level of compar- 
ative insignificance. 



16 PARIS UNIVERSAL EXPOSITION. 

It is remarkable that, vast as was the revolution which the steam, 
engine was destined to effect in the industrial world, the steps by which 
this was accomplished did not succeed each other with great rapidity. 
The first impression which the invention produced was in the relief it 
brought to mining. Its influence was next most distinctly felt in the 
development which it gave to textile manufactures. Then metallurgy 
yielded to its transforming power, and by degrees the same influence 
extended itself into every branch of mechanic art. But the applica- 
tions of the new power to locomotion upon the water and upon the 
land, applications which were destined to infuse into commerce a life 
and activity which it had never known before, and so to react upon 
production indirectly no less effectually than the same cause had already 
done directly, came at long intervals, and required the greater portion 
of a century for their full realization. It is interesting to observe how, 
in the infancy of a great invention, conceptions which are perfectly just, 
struggle painfully and often for a long time abortively, to embody them- 
selves into form. And it is sad as well as interesting to observe what 
chilling lack of sympathy usually attends their announcement, what 
obstinate prejudices rise up to oppose their introduction, what ridicule 
labors to dishearten their authors, and what contemptuous refusal of 
substantial aid operates to paralyze effort. The practicability of apply- 
ing steam to river navigation was repeatedly demonstrated before the 
close of the 18th century; but it was only after a lapse of forty years 
from the invention of the engine, that Fulton, in presence of a great 
multitude, assembled chiefly in the hope of finding amusement in his 
discomfiture, made at length the decisive experiment which was to force 
this important truth upon the convictions of men beyond the possibility 
of further question. Twenty years more elapsed before it was clearly 
seen in what way the same power might be made subservient to the uses 
of locomotion on the land ; and ten more still before the problem which 
had been so long completely solved for inland waters was admitted to be 
so likewise for the ocean. We stand at the end of the first quarter of 
a century since the Atlantic was bridged by steam ; and within that 
brief period the entire naval and almost the entire commercial marine 
of the world has undergone a complete transformation. The tonnage 
of vessels has been doubled, the duration of voyages has been dimin- 
ished more than half, and the interchange of wealth between nations 
has increased no less in quantity than in rapidity. The effect of all this 
upon productive industry everywhere is too vast to be computed. 

We have instanced, thus, in the first place, an invention which has 
revolutionized a single branch of industry; and in the second, one which 
has produced a similar effect upon all industries. But the industries of 
the world are constantly growing in number, and an invention may 
sometimes possess a character so original as to be the means of creating 
a new one. An example of this kind may be found in the vulcanization 
of India-rubber; a process which has made of a substance which but a 



RELATION OF INVENTION TO DISCOVERY. 17 

few years since was limited to the narrowest range of uses, if rather it 
might not justly be called more curious than useful, the basis of one of 
the most important of existing manufactures. Photography furnishes 
another example of the same class ; and this perhaps is a more happy 
selection, since the India-rubber manufacture can only be profitably con- 
ducted upon a scale of some magnitude, and is therefore concentrated 
in the hands of a comparatively small number; while photography 
adapts itself to all circumstances, and to the humblest resources, and 
may be practiced by an individual working alone in a garret, as well as by 
the operator on a grand scale whose saloons and laboratories occupy a 
palace, and whose assistants are numbered by hundreds. 

It may be questioned, perhaps, whether, in the examples just cited, 
the processes at the foundation of the industries which they have crea- 
ted should not be called discoveries rather than inventions. This ques- 
tion is unimportant to the object for which the examples are produced, 
since, for the present purpose, it is immaterial whether a new industry 
is founded upon an invention or upon a discovery. Yet for the sake of 
precision of ideas it may not be amiss to mark the distinction. Dis- 
covery is the extension of the field of knowledge, the unveiling of a 
truth which though pre-existing was before concealed. Invention is the 
combination of known instrumentalities, truths, facts, or material things, 
in a way before unpracticed, to produce a definite end. Discovery there- 
fore creates nothing. Invention creates. But knowledge, nevertheless, 
is the armory of invention, and every increase of knowledge increases 
the inventor's strength ; so that the steady relation between the advance 
of discovery and the correspondingly growing efficiency of productive 
industry constitutes the most striking of all illustrations of the truth 
of the adage that " knowledge is power." 

It follows from the distinction just drawn that a discovery may be 
accidental ; but that an invention, since it implies design and forethought, 
cannot be so. The discovery of the polarization of light was accidental, 
but the invention of the saccharimeter, founded on this discovery, was 
the result of study. 

A discovery, again, is sometimes made, which, while it can hardly be 
said to be purely accidental, is yet unexpected by the discoverer, who 
may be looking for something new, but not in the direction in which it 
presents itself. An example of this kind is furnished by the discovery of 
indium, brought to light in the study of the solar spectrum. Such dis- 
coveries may be called incidental. The early history of chemistry is full 
of them, and among the most important of the number may be ranked 
the mineral acids, evolved from their combinations by the alchymists of 
the middle ages in the course of their empirical pursuit of visionary 
objects. It is curious to observe how powerful has been the influence 
upon the history of productive industry of discoveries like these, coming 
unlooked for and unappreciated when made, but possessing, nevertheless, 
a potential value, in comparison with which the philosopher's stone itself, 
2 I A 



18 PAKIS UNIVERSAL EXPOSITION. , 

k the great object of the researches which made them known, would have 
been worthless. 

But although a discovery may often thus be made without effort or 
without intention on the part of the discoverer, it has occasionally a 
larger part in the foundation of an industry than any supplementary 
invention which may be necessary to draw from it a practically useful 
result. Such is not, however, the rule. More usually invention and dis- 
covery go hand in hand, and lend each other mutual aid. Discovery is 
constantly the basis of invention. The very first thought which presents 
itself on the acquisition to our pre-existing stock of knowledge of any 
new truth in chemical or physical science, is, what shall we do with it for 
the benefit of the human race? It is not always that we see for the 
moment what we shall do with it. The truths the most ultimately pro- 
lific have often continued to be for a time after their first announcement 
comparatively sterile. But the history of the past has shown that no truth 
is ultimately useless, while most new truths act almost instantaneously 
to stimulate invention. 

In the case of a few of the great inventions by which the world has been 
benefited, the effect has been to act more immediately and more power- 
fully upon the moral and intellectual character than upon the material 
condition of the human race. Pre-eminent above all others in this class 
must be ranked the capital invention of printing ; an invention which, 
by opening the way to universal education, has wrested the priceless 
treasures of knowledge from the possession of a favored few, and given 
them to be the common property of all mankind. Xor is the value of this 
grand invention full}' told, when we say that it has substituted knowledge 
for ignorance. Ignorance implies something more deplorable than merely 
not to know ; it implies superstition, credulity, cruelty, degraded tastes, 
mean and grovelling ambitions. An ignorant people is almost of neces- 
sity an enslaved people. Without capacity for combination, without 
expansiveness of views, unacquainted even with its own strength, and in 
slavery already to phantoms of the imagination, such a people succumbs 
easily beneath the yoke which a bold will and an iron hand impose. An 
ignorant people is also a people to a greater or less degree brutalized : a 
people whose better nature is obscured, whose larger capabilities are 
undeveloped, and whose most salient characteristics are too generally 
only low cunning, petty selfishness, and an obtuse moral sense. Deliv- 
erance from ignorance is emancipation from bondage, the awakening of 
the nobler faculties of the better sentiments and of the more generous 
susceptibilities of humanity, and the elevation of man to the position of 
dignity among created things which he has been capacitated by his Maker 
to occupy. Without the printing press such deliverance was no doubt 
possible, but it was possible only to the few; for the multitude, servitude, 
mental darkness, moral debasement, physical suffering, remained the 
inevitable destiny. Of such an invention the value can be measured by 
no ordinary or sordid standard. The industrial advantages which have 



THE ELECTRIC TELEGRAPH— GUNPOWDER. 19 

followed in its train are unworthy for an instant to be compared with the 
results of that beneficent influence which it has exercised over the minds 
and the hearts of men. 

A similar character, though not so distinctly marked, must be ascribed 
to the invention of the electric telegraph. The rapid diffusion of intelli- 
gence which this splendid triumph of human ingenuity has made possible 
between points most widely separated from each other upon the earth's 
surface, has contributed, and is contributing, much, though to common 
observation it may be insensibly, through the increase of knowledge 
which it brings, and through the lively stimulus it is affording to intel- 
lectual activity, to promote the growth of popular enlightenment through- 
out the world. It is probable that this invention is about to prove one 
of the most powerful instrumentalities ever known in breaking down the 
barriers between nations, in gaining acceptance for the doctrine of the 
solidarity of peoples, and in advancing the march of civilization over 
lands on which the shadow of barbarism is still resting. The telegraph 
is invading central Asia, and is menacing the heart of the Chinese empire. 
With such an agency constantly at work, another century cannot fail to 
effect, among the secluded peoples of those remote regions, changes, 
social, industrial, and possibly political, more signal and more singular 
than any that have taken place among them hitherto since the age of 
Confucius. 

There may seem to be something paradoxical in ascribing, as to some 
extent may certainly be justly done, a similar influence to an invention 
of earlier date, of which the immediate result was rather to arm men more 
effectually for each other's destruction than to draw them together into 
a common bond of brotherhood — the invention of gunpowder in the 14th 
century. Yet it cannot be denied that whatever tends to diminish the 
frequency of wars, or to lessen their horrors when they occur, is so far 
at least promotive of the spirit of peace. The strifes which take place 
between modern nations are no longer prosecuted with the sanguinary 
ferocity which marked the military conflicts of earlier times ; battles are 
no longer fierce personal struggles in which each man meets his adver- 
sary hand to hand; victory is no longer the signal for indiscriminate 
massacre, and the horrible war-cry vce metis has ceased to be the shout 
of the conquerors. The improvement may in some degree be due to the 
transforming power of Christianity in the later centuries, and to the soft- 
ening of men's spirits under the genial influence of an advancing civil- 
ization. Yet it has often been also attributed, and in measure at least 
with apparent justice, to an invention which, though it has rendered 
weapons more deadly, has made it henceforth unnecessary that the con- 
flicts of men should resemble the fights of tigers, and has made science 
an element of the art of war no less important than physical force. 

In classifying inventions as they affect the industrial world, we may, 
then, distinguish them in the first instance into two groups, according 
as they seem to be of primary or of secondary importance. In the former 



20 PARIS UNIVERSAL EXPOSITION. 

of these groups may be placed, first, inventions whose effect is to trans- 
form an industry already existing, and to give to it an increased relative 
importance; next, those which are the means of originating new indus- 
tries ; then those whose influence is not special, but is felt throughout 
the whole industrial field ; and finally, such as, in addition to their value 
as contributions to productive power in the material world, act directly 
as instrumentalities in promoting the mental and moral advancement of 
the human race. 

Among inventions of the second order of importance will be classed, 
of course, such as are avowed modifications or improvements, often very 
real, of those of the first; remedying the imperfections of an original 
process or machine, and contributing to a more satisfactory result ; then, 
such as, without creating a new industry or transforming essentially an 
existing one, facilitate or tend to expedite certain of the operations inci- 
dental to a manufacture ; then, such as add to the minor comforts, con- 
veniences, and enjoyments of life; and finally, such as, in place of the 
multitude of common objects and implements in daily use among men of 
all trades and professions, substitute others of improved form, or better 
material, or more moderate price. 

This classification may not be exhaustive, but of its propriety, so far 
as it goes, the Exposition furnished a large variety of illustrations. To 
illustrate the distinction by example, the original sewing machine may 
justly claim a place in the first group ; but its various modifications, its 
adaptations to embroidery, to harness-making, to the working of button 
holes, &c, must be referred to the second. The varieties of mechanism 
employed in the formation of the stitch in common sewing must all take 
the same direction. Some of these have evidently been devised not so 
much in the hope of a real improvement as for the sake of securing a 
patentable form of a popular machine. Among the number, however, it 
is but justice to distinguish one which possesses a very distinctive merit. 
The machines which employ but a single thread have the advantage of 
superiority in point of simplicity of construction and of facility of man- 
agement ; but they have the great disadvantage generally of producing 
a seam which, when it fails at a single point, fails everywhere. To make 
a seam with a single thread which will not yield when cut across is a 
very signal improvement ; and this result seems to have been effectually 
achieved in the machine of Wilcox & Gibbs, of Xew York. By an unfor- 
tunate mistake this machine did not come under the observation of the 
jury of the class to which it belonged, and it failed, therefore, to receive 
the recompense which was justly its due. Another illustration of this 
class of secondary inventions presented itself in the Jacquard looms. 
exhibited by Mr. Pinel de Grandchamp, of Paris. Iu the weaving of 
complicated patterns with these machines, the multiplicity of perforated 
cards which are necessary to govern the movements of the warp becomes 
an inconvenient incumbrance. The inventor has successfully disem- 
barrassed himself of this incumbrance by the simple expedient of substi- 



CLASSIFICATION OF INVENTIONS. 21 

tuting for the cards a continuous sheet of perforated paper. By this 
substitution there was secured at once the double advantage of superior 
convenience and diminished expense. Still another and very interesting 
illustration of similar character was seen in the power looms and knitting 
machines exposed by M. M. Eadiguet and Lacene in the same class. 
This consisted of an ingenious attachment designed instantly to arrest 
the movement, if at any time the spool became exhausted in the shuttle, 
or the yarn happened to break. A delicate metallic finger was seen to 
feel for the yarn at the very instant the shuttle completed its course. If 
the yarn was in its place it rested there, and the work went on ; if not, 
it made an electric contact, and the power was paralyzed in an instant. 
In pattern work the advantage of such an attachment will easily be 
understood. No time is lost in studying to find where the pattern began 
to be interrupted, and no trouble is necessary to set backward the Jac- 
quard guides. 

As an example of what is intended in the second subdivision of inven- 
tions of this order, may be mentioned Armstrong's machine for dovetail- 
ing, exhibited in the American section. The rapidity and accuracy with 
which this ingenious contrivance executes one of the most troublesome 
details of joinery, which it has hitherto been necessary to accomplish 
slowly by hand, was a subject of constant interest to crowds of admiring 
spectators. Most machine tools of which the purpose is special, and 
many of the inventions auxiliary to rural industry, may be referred to 
this subdivision. 

To the third subdivision belong whatever relates to furniture and 
dwellings, to modes of heating, illumination, and ventilation, to food and 
culinary operations, to wearing apparel, conveyances, cutlery, <&c, &c. ; 
and to the fourth, the various implements and tools used in the hand by 
men of all trades and professions. And in addition to these things there 
are, doubtless, many miscellaneous inventions which this classification 
is not sufficiently complete to embrace. 

If, in view of the distinctions which have been thus drawn between 
the different classes of inventions, we turn our attention to the novelties 
presented in the Exposition of 1867, we shall be led to infer — 

1. That the number of inventions entitled to be called new in the 
sense that they are here first made known or first publicly exhibited is 
not remarkable. It is natural that this should be so, since it is the inter- 
est of every inventor, so soon as he has perfected his title, to publish his 
invention as promptly and as extensively as possible, while until that time 
it is equally his interest to keep the knowledge exclusively to himself. 
So abundant, also, and so rapid are the means of intercommunication at 
present existing between civilized nations, and so numerous are the 
channels of intelligence which the press has provided for every indus- 
trial speciality, that no invention, no improvement, no important change 
of any description can take place anywhere without becoming almost 
immediately known, in character at least if not in detail, throughout the 



22 - PARIS UNIVERSAL EXPOSITION. 

•world. On the other hand, the number of inventions here presented, 
which are new in the sense that they are recent, is very large ; and if all 
which are of secondary, as well as those of primary, importance, or all 
which are only improvements on pre-existing inventions, are to he 
included, it is a great deal too large to be easily enumerated. 

2. The number of recent inventions illustrated in the Exposition which 
have effected, or are effecting, large changes, and even revolutions, in 
important departments of the world's industry, is very considerable ; and 
among these there are some which are destined to stimulate production, 
in the departments to which they belong, to an extent which we can as 
yet bat imperfectly estimate. It is in the nature of such influences to 
work out their results by degrees 5 and the magnitude of their importance 
is only perceived in proportion as these results become apparent. Yery 
conspicuous in this class must be ranked the improved processes which, 
in later years, have been introduced into the manufacture of steel; and 
yet, largely as these have already modified the metallurgy of the age, 
the benefits which must result from them to the industrial arts generally, 
and especially to mechanical, civil and military engineering, are only 
beginning to be felt. Galvanoplasty is another great invention of 
recent times ; but it is one of which the capabilities have been developed 
more gradually still. For a long time it was believed to admit of no 
more important useful application than to the reproduction of works of 
art ; but it is employed at present for the preservation of important 
structures of iron in situations of exposure, where they are liable to be 
rapidly destroyed by corrosion.; it is an invaluable auxiliary to the art 
of heliographic engraving ; it gives durability to the printer's type ; and, 
in one way or other, it contributes something to the perfection of almost 
every useful art. A few years since the numerous public fountains of 
Paris — huge structures of cast-iron — were rapidly becoming unsightly 
objects from the rust which accumulated upon their surfaces. They 
have been coated by the galvanoplastic process with a shield of copper, 
which completely protects them against further injury, and have, conse- 
quently, now all the beauty of bronze combined with the cheapness of 
iron. Thus inventions of the first order of importance are not seldom 
slow to be recognized as such ; and in regard to such an invention, the 
term recent must be applied with a larger latitude of meaning than is 
understood when we speak of one which produces its impression imme- 
diately. Of this latter description was the invention of the reaper, which 
took the world almost by storm ; and the same remark is true of the 
planing machine, the sewing machine, and other signal industrial inno- 
vations of analogous character. A machine, in fact, which performs a 
definite work makes its way much more rapidly than a process, or even 
a mechanical contrivance, of which the possibilities of application extend 
to many varieties of work. One of the former description may. there- 
fore, soon cease to be new, while one of the latter will be always new 
so long as the development of its capabilities continues to be progressive. 



CLASSIFICATION OF INVENTIONS. 23 

It results that whoever should attempt, in a great industrial display 
like the Exposition of 1867, to take note of every interesting invention of 
recent origin which the exhibition embraces, would attempt an imprac- 
ticable task ; and that whoever should propose to select from among the 
number such recent ones as are of most prominent importance, would be 
obliged to understand the word recent as covering a period of some 
years. Such a selection it is which has been attempted in the notices 
which follow; and in making the selection it has been a purpose kept in 
view to avoid, as far as possible, encroaching upon ground which, in the 
distribution of duty, had been assigned to others. This explanation 
may account for the omission of any mention in this report of many 
objects whose comparative importance would entitle them to occupy a 
conspicuous place in any comprehensive record which should be made 
of the memorable things embraced in this Exposition. 



CHAPTER II. 
MOTOES. 

Hot-air engines — Advantages and Disadvantages— Classification — Theoretic 
limit of economy— Ericsson's hot-air engine— Shaw's— Belou's— Roper's — 
Lauberau's — Wilcox's — Franchot's — Inflammable gas-engines— Otto and 
Langen's— Lenoir's — Hugon's — Ammoniacal gas-engines— Frot's— Delaporte's 
— Rotary steam-engines— Behren's— Pillner and Hill's— Scheutz's— Thomp- 
son's — Root's square piston engine — Hydraulic motors — Water-wheels — 
Turbine wheels— Water-pressure engines— Gtrard's hydraulic pivot— Aerial 
motors— Electro-magnetic engines— Cazal's — Birmingham Company's — Kra- 
vogl's. 

GENEEAL OBSEBVATIONS. 

Force being the first necessity in all industries, it is natural that the 
agencies designed to furnish motive power should receive the first atten- 
tion. The steam-engine, in its several forms fixed and movable, with 
the exception of the rotary engines, having been made the subject of 
examination and report by another committee, will require no notice 
here. It is sufficient to remark in this place that, notwithstanding the 
inappreciable usefulness of this machine, and notwithstanding the many 
and very great improvements which have been introduced into it since 
the time of Watt, the steam-engine is still not without some features 
which, if it were possible, it would be desirable to avoid. Though it has 
been reduced to a form comparatively compact, it still occupies an 
amount of space which is for many purposes inconvenient ; and though 
for a given power the cost of construction is less at present than it was 
a quarter of a century ago by more than fifty per cent., it is still costly. 
The improvements of boilers have very largely increased the amount of 
heat utilized, and have so reduced the bulk and weight necessary to the 
production of a given power as to have made the introduction of the 
movable engine into agriculture and into many of the minor industries 
economical, and not too inconvenient. Yet, for intermittent industries, 
the time consumed in raising steam to the required pressure, and the 
unproductive expenditure of fuel which is the consequence of the fre- 
quent repetition of this operation, are sensible disadvantages ; and to 
these must be added the disastrous effects which usually accompany the 
accident of an explosion of the boiler $ an accident which, however rare, 
is always possible, and against which no caution or foresight can pro- 
vide an absolute security. Much ingenuity has therefore been enlisted 
in the endeavor to provide a motor which, in certain circumstances, if 
not in all, might replace the steam-engine. If, as yet, the success of 
these efforts has not equalled the hopes of their authors, it has still been 



26 PARIS UNIVERSAL EXPOSITION. 

considerable, and it has probably by no means yet reached its culmi- 
nating point. The " motors" of this description which presented them- 
selves in the Exposition may be arranged under several heads, as follows : 
1. Hot-air engines 5 2. Inflammable gas-engines; 3. Ammoniacal 
gas-engines ; 4. Eotary steam-engines ; 5. Hydraulic motors ; 6. Aerial 
motors ; 7. Electro-magnetic engines. 

L—HOT-AIB ENGINES. 

Of engines driven by heated air, several varieties were exhibited. 
All of these have certain advantages in common, and all are subject to 
certain disadvantages which are inseparable from the system. It is an 
advantage that they require no boiler, and are exempt from the dangers 
which arise from that source. Could air be employed at a pressure 
equal to that of steam, it would be an important advantage to be free 
from the great weight which the use of the boiler necessitates, and 
unembarrassed by its bulk. As yet, however, this condition has not 
been realized, and hence the dimensions of the working parts of air- 
engines are necessarily so much more considerable than those of steam- 
engines of corresponding power, as to render the gain in this direction, 
if there is any, unimportant. It is, however, an advantage that air- 
engines are cheaper of construction than those driven by steam, and 
that their management is easier, and requires less constant watchfulness. 
It has generally been claimed for them that they economize fuel. Theory 
might seem - to justify this claim, but in practice it has hardly been 
sustained. 

The disadvantages of air-engines consist in the difficulty of heating 
and cooling the air employed with the rapidity necessary to secure the 
best performance; and in the fact that the supply of the cylinder con- 
sumes more than half the power developed. To this it may be added, 
that, while the efficiency of the machine depends upon the difference 
between the maximum and minimum temperatures, there are certain 
practical limits which neither of these temperatures can transcend. 

Air-engines may be arranged in two classes, of which the first embraces 
those which draw their supplies directly from the atmosphere, and dis- 
charge them into the atmosphere again after they have produced their 
effect; and the second, those which employ continually the same ah', 
which is alternately heated and cooled but is not allowed to escape. 
The Ericsson engine which has been established among us for many 
years, and which, for minor industries, is in so great esteem, is an 
example of the first class. The engine of Mr. Lauberau, which will pres- 
ently be described, illustrates the second. 

In each of these classes a subordinate classification may be made 
according as the air is heated in the cylinder in which it performs its 
work, or in a separate chamber. The plan of the Ericsson engine is 
the first of these. That of Mr. Shaw's invention exhibited in the Ameri- 



HOT-AIR ENGINES. 27 

can section, and also of Mr. Koper's in the same section, the second. 
Of machines which do not discharge the air, Mr. Lauberau's was the 
only one exhibited. In this, the work is done in one cylinder, and the 
heat is applied in another. This class of machines admits of several 
modifications of arrangement, all of which have been employed by 
different inventors with more or less success. The heater and the refrig- 
erator, for example, may be both independent of the working cylinder, 
and of each other; presenting an analogy to the boiler and condenser 
of "the steam-engine ; or the refrigerator only may be separate ; or finally, 
as in the engine of Mr. Lauberau, the heating and refrigeration may 
take place at the opposite extremities of the same vessel, the air being 
driven from one end to the other alternately by means of a plunger. 

Certain propositions are true of all these machines. In the first place, 
there is a theoretic limit to the economy of which they are capable — that 
is to say, of the heat which the air receives from the* source, a fraction 
only can under any circumstance be converted into mechanical force ; 
and theory enables us to state the maximum value which this fraction 
can have. This maximum depends only on the extreme temperatures 
at the command of the engineer; and is therefore the same for all hot- 
air engines, and not only for these but for all engines whatever driven 
by heat, whether the elastic medium employed be air or steam, or ammo- 
nical gas, or the vapor of ether or of any other volatile liquid. But in 
no engine yet constructed has this economical limit been reached, or 
even very nearly approached. 

As the proposition here stated is a very important one, it is proper to 
devote a few words to its illustration. Its truth is directly demonstra- 
ble from the principles of the mechanical theory of heat. In fact, when 
the elastic force of air or steam is employed as a motive power, the maxi- 
mum limit of possible advantage, and therefore of economy, is easily 
ascertained, by following the successive changes, in regard to volume 
and temperature, through which a limited portion of the elastic medium 
(a single charge, for instance, of the working cylinder) must pass, in 
order that it may produce the largest elementary portion of work of 
which it is capable, and be restored to its original condition, or to the 
state in which it may be available to produce a second useful effect. In 
practice this cycle is not usually completed; and the same portion of the 
elastic medium is not made repeatedly serviceable. At a certain point 
of its expansion, the steam or the heated air is discharged into the 
atmosphere, while a fresh portion is taken up to supply the place of that 
which is thus abandoned. When, in the case of steam, a condenser is 
used, the water produced by condensation is returned to the boiler; 
but here the regularity of the cycle is broken by the abrupt condensa- 
tion of the steam before it has performed all the work of which it is 
capable. On this account no steam-engine fulfils the conditions of largest 
economy. But the fraction of work which is voluntarily sacrificed could 
usually be saved only at the expense of a more than compensating incon- 



28 PARIS UNIVERSAL EXPOSITION. 

venience. In the case of steam, the cycle of changes which takes place 
in the production of the largest possible amount of available force of 
which a given volume of the medium is capable, consistently with the 
supposition that it is finally restored to its original state, so as to permit 
a repetition of the effect, is the following : 

First. The large expansion attendant on the conversion of water into 
steam with the volume due to the temperature and pressure of the boiler. 

Secondly. The dilatation of this steam with diminishing pressure and 
temperature, until its elastic force is in equilibrium with that of the sur- 
rounding media — of the atmosphere, in the case of a non-condensing 
engine, and of the vapor in the condenser, in a condensing engine. 

Thirdly. The reduction of the volume of this steam, or mixed steam 
and water, without elevation of temperature, (that is, with a constant 
abstraction of the heat produced by the compression,) to such a bulk that, 

Fourthly, a final compression, without abstraction of heat, shall restore 
it to the boiler in the form of water under the original temperature and 
pressure. In the third step of this progress the force required for the 
compression is constant, and is simply that which is necessary to clear 
the cylinder against the resistance of the atmosphere or of the vapor in the 
condenser ; but it is attended with progressive condensation of the vapor 
still remaining to the form of water $ the latent heat thus developed being 
supposed to be removed by suitable means of refrigeration. In the final 
compression it is the force of increasing pressure which completes the 
condensation ; and the developed latent heat brings up the temperature 
of the water to that of the boiler. In this series of changes, the expan- 
sion in the first term and the compression in the third are attended with 
no change of elastic force, since the temperatures remain constant, and 
the densities also ; vaporization, on the one hand, and condensation 
on the other, compensating for change of volume. In the first stage heat 
is constantly received from the fire ; and in the third it is constantly 
abandoned to the refrigerator. In the second and fourth no heat is either 
received or given up. There is constant loss in every stage by the effect 
of radiation and conduction ; but this, in the abstract theory, is not con- 
sidered, and in practice is guarded against as far as possible. When 
the medium employed is air, or a permanent gas, the cycle of changes 
is similar, but the pressures are variable throughout. In the first and 
third stages the temperatures are constant, as in the case of steam. In 
the second the temperature falls, and in the fourth it rises. During the 
first stage heat is received from the fire in such quantities as to prevent 
any depression of temperature in consequence of the expansion, but not 
enough to produce any elevation of temperature* This heat is entirely 
converted into work, and is the exact equivalent of the work done in this 
part of the cycle. During the second no heat is received or given up : 
but the temperature falls, and the work done is the equivalent of the 
heat which thus seems to disappear. In the third the volume is reduced 
by compression, and a refrigerator absorbs the heat which the compres- 



LIMIT OF ECONOMY IN HOT-AIR ENGINES. 



29 



sion developes, so as to maintain a constant temperature ; and in the 
fourth further compression elevates the temperature to that with which 
the cycle commenced, while at the same time it restores the original 
bulk. In this change the temperature rises through as many degrees as 
it fell during the second period ; and the same amount of heat which 
then seemed to disappear now makes its re-appearance. The work done 
with positive effect in one of these two stages balances that which is 
expended unprofitably in the other ; so that the amount which is finally 
available for use is the difference between the work which is performed 
during the expansion in the first stage and that which is consumed in 
the compression which takes place in the third. And this, as we have 
seen, is measured by the heat received from the fire, diminished by the 
heat imparted to the refrigerator. 

The foregoing propositions may be visibly illustrated by means of a 
simple geometrical figure. If we suppose a body of air, or other elastic 
medium, to be confined in a cylinder between the closed extremity and 
a movable piston, the distance between this extremity and the piston 
will be always proportional to the volume. In the annexed figure let O 




Fig. I. 

be the closed extremity of the supposed cylinder, and A 7 , B 7 , C 7 , D 7 , posi- 
tions occupied by the movable piston at the end of the successive stages 
of expansion and compression which we have supposed the air to 
undergo. Then let AA 7 , BB 7 , CO 7 , DD 7 be perpendiculars proportional 
to the pressure exerted by the air upon the piston at those several points. 
The first stage of expansion is represented by the movement of the piston 
from A 7 to B 7 , during which the temperature is constant, and the pres- 
sure falls off gradually. The work which is done during this period is 
proportional to the area ABB 7 A 7 . The second stage of expansion cor- 
responds to the movement of the piston from B 7 to C 7 . During this period 
no heat is supplied by the source, and the temperature falls. The pres- 
sure also diminishes more rapidly than before, and the work done" 
is proportional to the area BC0 7 B 7 . The first stage of compression 
occurs while the piston moves from C 7 to D 7 , in the direction opposite to 
that of its former movement ; and as, during this period, the refrigerator 
removes the heat generated by compression, the temperature remains 
constantly the same, and the work consumed in overcoming the resist- 
ance of the air is proportional to the area CC 7 D 7 D. Finally, in the move- 



30 PARIS UNIVERSAL EXPOSITION. 

ment of the piston from D' to A', its original position, the refrigerator no 
longer acts, and the temperature rises, the pressure rising at the same 
time more rapidly than before. LV may be taken at such a point that 
the final pressure shall be equal to the initial pressure AA'. In this last 
movement, therefore, the work consumed will be proportional to the area 
DD'A'A. 

Thus we have, for the positive effect of expansion, the entire area 
ABCC'A'. But, in order to restore the air to its original state, there 
must be expended a force represented by the area ADCC'A'. And it is 
only the difference between these two values, or the force which has the 
irregular area ABCD for its representative, which is available for useful 
effect. 

It is provable that the area BOOB, described under these circum- 
stances, is equal to the area ADD'A'. Hence, in fact, the area repre- 
senting the available force ABCD is equal to the difference of the areas 
ABB / A / and DCC'D'. The first of these areas is that which is described 
with the superior temperature constantly continued ; and the second that 
which is described with the inferior temperature similarly constant. 
The other two effects, being equal and opposite, may be disregarded. 

Now the heat consumed in expanding an elastic fluid through a space 
bearing a definite proportion to its bulk without change of temperature, 
(which is the measure of the work done at the same time,) must of course 
be proportional to the pressure ; and this is itself proportional to the 
temperature measured from the absolute zero, two hundred and seventy- 
three degrees below the zero of the Centigrade thermometer. And the 
heat developed in compressing a similar fluid through a similar space 
must, for the same reason, be proportionate also to its temperature. The 
actual bulk of the air during the expansion in the first stage of the cycle 
above described, and during the compression in the third stage, is not the 
same ; but the ratios of the bulks at the beginning and end of the expan- 
sion, and at the beginning and end of the compression, are equal, and 
accordingly the quantities of heat received in the first instance from the 
fire, and imparted in the second to the refrigerator, are proportioned to 
the temperatures at which the expansion and compression take place. 
It hence appears that, of the heat required to operate an air-engine which 
fulfils the conditions above described, the proportion which is converti- 
ble into useful work will be greater or less, according as the maximum 
and minimum temperature differ more widely. And what may be called 
the coefficient of economy for such an engine may be thus expressed : 
. If T be taken to represent the superior temperature measured from the 
absolute zero, and T' the inferior; and also Q to represent the quantity 
of heat received from the fire during the first expansion, and Q' the quan- 
tity transferred to the refrigerator during the first compression : and 
finally, if A represent a constant quantity dependent on the absolute 
pressure and bulk of the gas at a given temperature, then we shall have. 
Q=AT; Q'=AT'; Q— Q'=A(T— T'.) 



LIMIT OF ECONOMY IN HOT-AIR ENGINES. 31 

As Q — Q' is the portion of the heat utilized, and Q the entire amount 
received from the fire, the economical coefficient, or the fraction show- 
ing the ratio to the whole of the part which is made usefully available, 
and which may be represented by U, will be, 1 

Q_Q' A(T— TO T— T' 



U 



Q ~~ AT " T 



1 If the effects of the several movements described in the text are expressed analytically, 
the truth of the propositions above stated will be evident from a mere inspection of the 
formulae. 

Let it be premised that whenever a determinate mass of air, or other perfectly elastic 
medium, changes its volume without changing its temperature, the pressure will be inversely 
proportional to the volume. That is, if p a and v & denote a given pressure with its corre- 
sponding volume, and p n and v n any other pressure and volume coexisting, then 

p* : pn :: v n : v a ; or p JX v rx =p a v a . (i.) 

Also, if while volume varies the temperature varies, but pressure remains constant, then, 
putting t a and t n for the given and variable temperatures, respectively, as measured from 
the absolute zero, the temperature must vary as the volume, or 
t& I t n ;: v a I v n ; or t n v & — t a Vn. 

And, if the pressure varies while the volume remains constant, 

t a : t n :: p a : p n ; or t u p a =t a p n . 

Accordingly, if temperature, pressure, and volume all vary together 

t a : t n :: p & v & : p n v n ; or t n p a v a =t a p n v n . (ii.) 

Finally, if the same determinate mass varies in volume without receiving or parting with 
heat, 

fa : fa :: »/~ x : o/" 1 ; ^ l f=~' «* ^. = ^ r ' 1 ^ r ' 1 . ( n L) 



*5_ \^i 

V* 



m 



In which y is the thermo-dynamic index of the medium, or the ratio of the specific heat 
at constant pressure to the specific heat at constant volume. In the case of air, y= 1.421. 

Now if pi, p-2, pz, and p 4 denote the pressures at the commencement of the successive 
movements described in the text, severally; and vi, v%, v%, and V\ the corresponding volumes 
at the same time ; and if t a and ti, be the two extreme temperatures, and Wi, W2, W 3 , and 
W 4 represent the amount of force expended or work done in these movements, respectively, 
then the total useful effect resulting from the whole series, W u , will be expressed in the 
equation, 

W u =Wi+ W 2 — W 3 — W 4 . 

Of these the values of the second and fourth are — 

(y-1 y-i \ / y-1 y-l \ 
v -i =5 V and W 1 = Hi^f Q =a \ . 

Here p<i v 2 = pi »ii because the temperature from v x to % is constant and equal to ^ a , (I.) 

y-l y-1 y-1 y -\ 
Also, (III), 2? Z* <£=$> * =5 • 

Hence We=W4, and the equation is reduced to, 

w u =w,-w 3 . 

The values of these two terms are — 

Wi=pi vi h. 1. ~ V and W 3 = p 4 vAh.l.~\. 



But, (IV), Ei^/^V- 1 ^. Consequently H^Jl 

Vi \t\> J V<3, Vi Vi 



32 PAEIS UXIVEKSAL EXPOSITION. 

It follows that, in proportion as the interval between T and T' is 
increased, the machine will work with correspondingly greater economy. 
This interval can be increased by increasing T, or by diminishing T', or 
by doing both at once. It is impracticable, however, to employ a refrig- 
erator having a temperature below that of the weather. We must there- 
fore take for a mean lower limit about 17° C. or 62° 5 F, a temperature 
which, referred to the absolute zero, is equal to 290° C. On the other 
hand, a x>ractical upper limit is imposed by the consideration that a red 
heat is reached for solids at about 650° C. which is 923° C above the 
absolute zero. This limit could not be safely approached : but supposing 
it to be actually attained, the economical co-efficient would be 

923 — 290 naQA 
—^3— =0.684 

or a little more than two-thirds of the heat taken up by the air. Proba- 
bly no hot-air engine has yet been actually employed, in which the tem- 
perature has been carried much above 300° C. With a maximum tem- 
perature of 307° C == 580° C above the absolute zero, the economical 

coefficient would be 

S 80 - 290 = 0.50 

oSO 

which would show a utilization of -one-half the heat taken up. The first 
Ericsson engine was designed to work at a maximum temperature of about 
450° F = 232° C = 505° above the absolute zero. The limit of economy 
realizable by it. had it been successful, and provided the air could have 
been made to pass through the complete cycle of changes embraced in 
the theory, would have been 

505 - 20 ° =0.4?6. 
oOo 

But in point of fact, no hot-air engine fulfils, or can fulfil completely, 
the theoretic conditions. In order to do so. it would be necessary that 
the aii 1 should leave the working cylinder at the minimum temperature : 
that is to say. at a temperature as low as that of the supply : or else that. 
by some contrivance, the excess of heat which it retains should be trans- 
ferred to the supply on its way to the working cylinder. As the first 
of these conditions — that is to say. the expansion of the air in working 
sufficiently to reduce the temperature to the minimum — is practically 
unrealizable, it is the second which inventors have in many instances 



Pi »i 



Also, (II), f b pi vi = f a p 4 ti : and p 4 v 4 = f ^ 

Hence W„ = Wi — ^Wi =W, ( U ~ tb 1 • and — u _ ' a ~' b 

f a V fa / Wi~ f a 

Thus, as V\~! is the mechanical equivalent of all the heat that has been imparted to the 
medium, the fraction expressing the greatest possible useful effect, or the economical cotjicitnt. 
is formed by taking the difference of the extreme temperatures for a numerator, and the maxi- 
mum temperature for a denominator. 



HOT-AIR ENGINES REGENERATORS. 66 

sought to secure. In order to accomplish this, the emergent air has in 
some cases, as in Ericsson's original engine, been made to pass through 
successive sheets of wire gauze, or between thin sheets of metal, or has 
been in some other manner brought into contact with metallic surfaces 
of large extent in proportion to the weight of the mass, in order that the 
excess of heat being transferred to these might be afterwards taken up 
by the cold air of the supply as it enters. The first of the expedients 
here mentioned was employed by Mr. Ericsson, and the second in the 
earlier invention of Sterling. In Shaw's engine, exhibited in the Exposi- 
tion, the hot air escapes through a cluster of thin tubes, while the cold 
air circulates between them. The term " regenerator" was applied by 
Mr. Ericsson to this contrivance as applied to his original engine, and 
this term has come into general use. The regenerator is applicable to 
any form of engine, but it is not employed in all. The theoretic advan- 
tage is considerable, but in practice is not fully realized ; and it is attended 
with the disadvantage of sensibly increasing the amount of the passive 
resistances of the machine. In fact, in order that the regenerator, sup- 
pose it for instance to be a succession of wire gauze sheets, should entirely 
absorb the excess of heat of the escaping air, the number of sheets should 
be very considerable. It is easily seen that if this number were quite 
unlimited, there would be somewhere a point at which the air would have 
no longer any heat to impart ; its temperature being sensibly reduced to 
that of the metal. From this point backward to the cylinder from which 
it was discharged, the successive sheets of wire gauze would rise in tem- 
perature, and the last one would have sensibly the same temperature as 
that with which the air emerged. The number of sheets which would be 
required effectually to absorb the heat, would depend, for a given excess 
of temperature, upon the closeness of the meshes, and in any case must 
be considerable. The obstruction which every such contrivance necessa- 
rily presents to the free passage of the air, creates a resistance which 
makes its presence objectionable, and which may go far to neutralize the 
advantage which it is designed to secure. By diminishing the number 
of the sheets and the closeness of the meshes, the resistance is reduced, 
but the absorption of the heat is proportionally less complete. Practi- 
cally, where the regenerator continues to be used, a middle course is 
taken ; the economy is not wholly realized, and the obstruction to circu- 
lation is not very serious. This is the case in the engine of Mr. Shaw, in 
which the regenerator consists, as above remarked, of a series of tubes. 
It is to be considered, however, that the loss of heat suffered in operating 
engines driven by heated air or steam, is by no means limited to the 
fraction, large as it is, of the heat which, after being actually imparted 
to the medium, is unavailable for work. If this were true, the cost of 
working such engines would fall to a very small proportion of what it 
actually is. It is, unfortunately, the case that by far the largest source of 
loss is to be found in the escape of a large part of the heat which the 
combustible develops in other ways than in raising the temperature of 
3 i A 



34 PAEIS UNIVERSAL EXPOSITION. 

tlie elastic medium which does the work. And tlie improvement of all 
these engines, so far as economy is concerned, is to be sought in such 
forms of furnace, and such modes of applying heat, as may reduce what 
is now the sheer waste of the chimneys or of the radiating surfaces, 
rather than in the endeavor to push to extremes the temperatures 
employed in the working cylinder. 

It is to be observed that the difficulty of guarding against losses by 
conduction and radiation is enormously increased when excessive tem- 
peratures are employed ; and also that such temperatures decompose 
lubricants, destroy packing, and, by the large expansion which they give 
to metals, loosen joints and impair the strength of the whole structure. 
Since the largest room for economy is evidently in the direction of pre- 
venting the wholly useless waste at present occurring, the effort should 
be to keep the maximum temperature as low, and not to push it as high, 
as possible. 

ERICSSON'S ENGINE. 

The engine of Mr. Ericsson is too generally known to need many words. 
In its present form it differs essentially from that which it had when 
constructed on a large scale, some fifteen years ago, to be employed as the 
motive power of a sea-going vessel ; or, more properly, the present one is 
a different machine. In the original model a working cylinder was placed 
immediately over the fire of the furnace, and a cylinder of supply of about 
two-thirds the capacity was placed immediately over that. The engine 
was single-acting, the working cylinders were quite open, and the working 
pistons were of great bulk and formed of non-conducting substances, being- 
designed to fill the cylinders when at the point of the lowest depression, 
so as to prevent their cooling by contact with the air of the atmosphere. 
The bottom of each cylinder was arched, forming a dome for a furnace : 
and the piston received, at its lower surface, a corresponding figure. 
The pistons of the supply cylinder and working cylinder were firmly con- 
nected, and had therefore an equal length of stroke. At the descent of 
the piston the supply cylinder was filled by aspiration from the atmo- 
sphere; and in the ascent the charge, after undergoing compression, was 
driven into a reservoir, from which it passed subsequently into the work- 
ing cylinder. The upward stroke being completed, the heated air escaped 
through a regenerator formed of wire gauze, depositing there its ex 
of heat; and the new charge from the reservoir, passing to the working 
cylinder through the same regenerator, re-absorbed this heat, and thus 
entered the heating chamber already at an elevated temperance. 

This engine, it will be seen, was remarkably simple in construction. It 
also performed very well in practice, so far as its performance was merely 
a question of mechanics. But it failed, because the heating arrange- 
ments were inadequate to the demand made upon them. Mr. Ericsson 
did not expect to be dependent on his furnaces for the supply of more 
than a moderate fraction of the heat which each successive charge of air 



ENGINE. 35 

was to receive. It was Iris anticipation that the regenerators would 
serve to transfer so large a quantity from each charge to the next, that 
it would be necessary to provide for little more than the always inevita- 
ble loss by mere radiation. This anticipation was not realized, and in 
fact could not be, since no account was taken of the large amount of 
heat necessarily transformed into work. But there was a canse of failure 
superadded to this, arising from the difficulty of heating air at all by 
means of a furnace. Eadiant heat produces scarcely any impression 
upon a body of air through which it passes. The inventors of all the air 
engines which have been to any degree successful have recognized the 
necessity of applying their heat as much as possible by conduction and 
actual contact. Mr. Ericsson himself is no exception, as his engine pre- 
sented in the Exposition shows. This machine possesses a special inter- 
est, from the fact that it was the first of its class to secure for itself a 
recognized place in the industrial world as a valuable aid to productive 
power. 

In its present form the Ericsson engine fails to present to the observer 
a combination at first view easily intelligible. It even seems to be 
characterized by a certain amount of complication, which might suggest 
greater liability to derangement than ought to belong to a prime mover. 
A closer examination, nevertheless, will show that the mechanism itself 
is iu fact very simple, and that it is only the rather puzzling consecution 
of movements which confuses. 

Before referring to the figure of this engine, which is given in Plate I, 
the following general explanation of the mechanical principles of its con- 
struction will be understood. Let it be supposed that a piston moves 
air-tight in a cylinder which is closed at both ends. Call one end of the 
cylinder A, and the other B. Call the piston also 0. In the end A 
let there be a valve opening inward, and in the end B a second valve 
opening outward. These two valves open, then, in absolute direction, 
the same way. Let the piston 0, furthermore, have a valve opening in 
this common direction. Then, if the piston move toward B, its own 
valve will naturally close, and that of B will open, because the move- 
ment tends to compress the air between B and C. Also the valve A 
will open at the same time, because the movement tends to rarify the 
air between A and B. Thus, in this movement, continued to the end of 
the cylinder, all the air on the side toward B may be expelled ; but at 
the same time the cylinder will be filled on the other side toward A, by 
the influx of air from without. If the piston C now reverse its motion, 
both the valves A and B will be closed, because the movement will 
tend to rarify the air on the side of B, and to condense it on the side 
of A. But its own valve will be opened by the joint effect of these 
causes, so that the air will pass freely through the piston; and if the 
motion continues, will ultimately be all transferred to the side of B. 
This operation may go on indefinitely. 

Now if, on the side of A, the cylinder is closed by a second piston 



36 PARIS UNIVERSAL EXPOSITION. 

(which we may still call A,) and not by a fixed cap, both pistons being 
movable, the same succession of occurrences will take place, only modi- 
fied by the movements which may be given to A. If C and A both 
move in the direction of A, both their valves will open, and air from the 
exterior of the cylinder will pass through both into the space between 
B and C. If they both move toward B, but G faster than A, then air 
will enter on the side of A, and flow out on the side of B, the valve 
only remaining closed. If both move toward A, but A faster than C, 
air will still enter the space between C and A, while, in less quantity, it 
is passing through C into the space between C and B. 

Let now the piston A be supposed to occupy a position, say one-third 
advanced down the cylinder, the piston C being further advanced still, 
and let the valve of B be secured by a strong spring pressing upon it, 
so that it cannot be opened without the application of some considerable 
force ; and in these circumstances let the cylinder, and consequently the 
air contained in it, be heated. The elasticity of the confined air being 
increased by heat will close the valve in A, and that piston will be moved 
in the direction of A, until, by the enlargement of volume, the elasticity 
shall be reduced to equality with that of the external air. If the heat 
be uniform throughout all the mass of confined air, the valve in C will 
be equally pressed on both sides. Under these circumstances the piston 
C could be moved toward A, if there were any means of acting upon it, 
the air passing through the valve toward B. But if an attempt were 
made to move the piston itself toward B, it would encounter resistance, 
because its own valve would be closed by the movement, and the valve 
of B is supposed to be forcibly held down. Since now the external piston 
must move in the direction A, it is only necessary that it should be 
properly connected with a machine, in order that the force exerted by 
the heated and expanding air may be turned to some practical account. 

If, again, at the end of the movement, the air could be immediately 
cooled without being discharged, the heat could be again applied and 
the effort repeated. But this not being practicable, the heated air may 
be allowed to escape by relieving the valve B of the pressure of the 
spring which confines it, and by causing the piston to descend to the 
extremity B of the cylinder. This movement of C not only drives out 
the hot air, but it draws in through A a fresh supply of cold air : and if 
A descends simultaneously to the position originally supposed, i. c. one- 
third advanced toward B, there will be a body of air filling the other 
two-thirds of the cylinder at the common temperature, ready to be acted 
on anew by heat. 

In this statement is embraced the general principle of the Ericsson 
engine. What remains is to explain the mechanical contrivances by 
which the movements of the pistons are governed, and to describe the 
heating apparatus which is employed to effect the prompt dilatation of 
the air. Inasmuch as the piston which we have called C is shot up in 
the cylinder behind A, it is necessary that the rods which give it motion 



Ericsson's engine. 37 

should pass through A. They do so, being packed by means of stuffing 
boxes to prevent leakage; and are connected at their external extremi- 
ties with oscillating levers turning on a fixed centre of motion at their 
extremities, and kept in motion by the engine. The rod of the external 
piston, A, which is the driving piston, is also connected with an upright 
oscillating lever, turning on an axis of motion at its lower extremity, 
and carrying at its upper a horizontal connecting rod which acts on 
the crank of the main shaft of the engine. It would be simpler to 
connect the piston directly with this crank; but if that mode of con- 
nection were adopted, the stroke of the piston would have to take place 
in both directions, forward and back, in equal times. This condition is 
not favorable to the action of the machine; and inequality in this respect 
is still more important in the case of the supply piston. The peculiar 
ingenuity of this machine is in fact manifested most signally at this 
point. By means of the systems of levers interposed between the pis- 
tons and the main shaft, provision is made for the perfect uniformity of 
the revolution of the shaft, while the pistons on the other hand are 
accelerated and retarded in such a manner as to fulfil the condition that 
the aspiration of the charge of air should occupy the minimum of time. 
The oscillating levers which connect with the piston-rods of the supply 
piston are kept in oscillation by crank motion from the main shaft, and 
in their oscillations they displace the inner piston, encountering no resist- 
ance but friction. In consequence of the un-uniform and unequal veloci- 
ties of the two pistons, and their intentional adjustment so that they do 
not begin and end their course together, the distance between them 
varies in a manner which is quite important, first to the aspiration of 
the charge, and secondly to the effectual exposure of the aspired air to 
the action of the furnace. 

It is of course of the highest importance that the positions of the 
cranks on the main shaft, and those of the axes of motion of the oscilla- 
ting levers, should be so related to each other as to produce a rapid 
separation of the two pistons at the beginning of the negative stroke ; 
because this is the time when the aspiration of the charge must take 
place. During this time, the inner piston, gaining on the outer, will not 
only draw in the fresh charge, but it will expel the exhausted one; the 
escape valve being lifted for the purpose and kept raised during all the 
period of aspiration by means of a cam. When the pistons are at the 
maximum distance from each other, the aspiration is ended. From this 
time until the half revolution is complete, the confined air undergoes 
compression, and the movement is maintained by the fly wheel. In the 
second half revolution the driving piston is urged by the elasticity of 
the air which is exalted both by compression and by heat. 

The heating is accomplished as follows: The furnace is within the 
cylinder, at the end which we have called B, where the cylinder is pro- 
longed to receive it. It is of iron and is cylindrical also, a small annular 
space only intervening between its walls and those of the cylinder. This 



38 PARIS UNIVERSAL EXPOSITION. 

space is open to the interior, but is closed at the extreme end; so that 
ir forms in fact a portion of the proper air chamber. To the supply 
piston G is attached by its crown a sheet-iron cylindrical bell, which 
enters the annular space just spoken of without touching the walls of 
the furnace or those of the surrounding cylinder. The valve in C opens 
above the crown of this bell $ but any air which comes through the valve 
from the side of A can only reach the interior by passing down the 
annular space between the bell and the cylinder wall, and returning up 
the annular space between the bell and the wall of the furnace. In 
making this passage, it will be exposed in a very thin sheet to the action 
of the furnace heat: a very large proportion of the molecules being 
brought into direct contact with the heated iron. 

That we may understand how this movement of the air is made forcibly 
necessary, we need only consider the relative movements of the pistons 
during the period of a complete revolution. At the beginning of the 
negative stroke, or of the movement of A in the direction of B, the 
supply piston takes the lead, air enters through the valve of A. and the 
aspiration is soon complete. The distance between the two pistons. 
which determines the amount of aspiration, is now of course at its maxi- 
mum. A next begins to gain on C, but both movements have still for a 
short time the same (negative) direction. The space occupied by the 
air is gradually reduced ; or, in other words, the air undergoes compres- 
sion. The piston C reaches the limit of its course sooner than A. It 
begins to move in the positive direction, while the motion of A is still 
negative. The valve in G is opened by the pressure, the air passes 
through and having no other channel descends the annular space outside 
of the bell and returns by the annular space inside the bell, becoming 
heated, as above described, in its progress. Presently after this dis- 
placement commences, the piston A also reaches its limit of movement, 
and the direction of its motion becomes positive. But C moves the 
faster of the two, so that the displacement continues throughout the 
greater part of the positive stroke. A little before the end. the distance 
between the two pistons becomes minimum; and they are then nearly 
in contact. When the revolution is quite complete this distance is 
slightly increased. Just before this time, C will have recommenced its 
negative movement, while A continues still to be moving in the positive 
direction. 

The relative movements here described will be more advantageously 
compared by presenting them in tabular form, which we are enabled to 
do by the help of the determinations made by Mr. Mastaing, of Paris, 
upon the Ericsson engine which was made the subject of experiment in 
1861 at the Conservatoire des Arts et Wtiers. by Mr. Tresca. sub-director 
of that institution. In the first column of this table are placed the 
angular positions of the driving crank on the main shaft at different 
periods of the revolution; putting zero to represent the position of the 
crank when the piston A is about to commence its negative stroke. The 



ERICSSON'S ENGINE. 6V 

second column gives the direction of motion of the driving piston, and 
its motion relative to that of the other; and the third column gives the 
same particulars in regard to the supply piston. The last column gives 
the variation of distance taking place between the two pistons at the 
several points indicated in the table. 



Angular position of the crank. 


Relative motion of the pistons. 


Distance 


Driving piston. 


Supply piston. 


pistons. 


o 
to 70 


Negative, losing 

Negative, equal 

Negative, gaining .. 
Negative, gaining .. 
Negative, contrary.. 

Limit of course 

Positive, losing 

Positive, losing 

Positive, gaining — 
Positive, gaining . . . 
Positive, contrary ... 


Negative, gaining .. 

Negative, equal 

Negative, losing 

Limit of course 

Positive, contrary. .. 
Positive, gaining . . . 
Positive, gaining - . . 
Positive, gaining . . . 

Positive, losing 

Limit of course 

Negative, contrary.. 


Increasing. 
Maximum. 


70 


70 to 120 


Decreasing. 
Decreasing. 
Decreasing. 

Decreasing. 
Decreasing. 
Minimum. 


120 


120 to 170 


170 


170 to 310 


310 


310 to 340 


Increasing. 
Increasing. 
Increasing. 


340 


340 to 360 





It will be seen that the negative stroke is completed in less than half 
a revolution, for either piston, while the positive stroke requires more; 
also, that this inequality is considerably greater for the supply piston 
than for the driving piston. In the case of the driving piston the 
inequality is as 170° to 190° ; in that of the supply piston, as 160° to 200°. 
These inequalities, which could not exist if the connection between the 
main shaft and the pistons were made directly, as in the steam-engine, 
are the effect of the intermediate system of levers, and are intentionally 
produced. The increase of distance between the pistons from 310° to 
the end of the revolution is not an advantage, but it is not a great increase, 
the total distance amounting finally only to about the one-sixth part of 
the maximum separation, and receiving the principal accession to its 
amount between 350° and 360°. As after the second reversal of the 
movement of the supply piston, the effective power of the engine is neces- 
sarily paralyzed, the escape valve is opened at 344° by the action of the 
cam above spoken of, and the aspiration commences before the revolu- 
tion is quite complete. The valve is closed again at 69°, just as the 
aspiration is becoming maximum. 

Inasmuch as the effective power of this engine is negative or zero from 
344° onward to 170°, or through a little more than half a revolution, it 
is necessary that the machine should be provided with a heavy fly-wheel 
to maintain the movement during these intervals. The fly-wheel is made 
to act also as a sort of counterweight, as well as by means of its moment 
of rotation, the side of the wheel which is descending during the period 



40 PARIS UNIVERSAL EXPOSITION. 

of paralysis being made considerably heavier than the other. A com- 
panion engine to act positively during the inaction of the first, would 
render such an expedient unnecessary; but unfortunately the bulk is 
considerable relatively to the power, and it would, in general, be a dis- 
advantage to double it. 

The engines of Mr. Ericsson are largely in use in the United States ; 
but as yet they have not been constructed of any considerable power. As 
a general rule they fall within three or four-horse power as an outer limit ; 
though it is believed that there have been made some exceeding this 
limit. On account of their safety and convenience they have been 
regarded with favor ; and it has been claimed for them as an additional 
recommendation that they are economical. Such did not appear to be 
the feet in the case of the particular engine which was the subject of the 
experiments of Mr. Tresca above referred to. In this machine, which 
was of two-horse power, the result of very careful trial showed a con- 
sumption of 4.13 kilograms (about nine pounds) of coal per horse-power 
per hour. In comparison with steam this cannot be called a large econ- 
omy. The consumption of a good steam engine ought not to exceed, per 
horse-power per hour, two kilograms at the outside. One and a half 
ought to suffice. 

It may be observed, in conclusion, that Mr. Ericsson makes no attempt 
to carry the temperature in this engine to a very high point. The mean 
maximum temperature in the experiments at the Conservatoire did not 
exceed 270° Fahrenheit, though doubtless portions of the air received a 
greater degree of heat than this. The expansion of volume was further 
determined to be but as 1 : 1.48 — that is to say, about fifty per cent, of 
the original bulk. 

The general description here given will be made more intelligible by 
reference to the figures of the engine given in Plate I. One of these. 
Fig. 1, is a longitudinal section through the axis ; and the other, Fig. 2, 
a cross-section through the furnace. 

Of the two pistons shown at A and F, the first, A, is the driving pis- 
ton, and the second the supply piston, which in the foregoing explana- 
tion we have called C. In A is seen a valve marked a. 

At B is an axis of motion, the office of which is to communicate move- 
ment to the piston A, by means of a crank o, a connecting rod j). a second 
crank g, and another rod r. 

In the piston F the valve of communication is shown at /. The solid 
portion F' is filled with plaster or other badly conducting substance, 
while F" marks the bell-shaped prolongation which extends into the 
annular space surrounding the furnace. VThen by the approach of the 
piston F to the piston A, the space between these two pistons is reduced. 
there is no escape for the air between them but that which is afforded 
by the annular cavities between this bell and the external wall of the 
machine /', on the one hand, and the wall of the furnace itself on the 
other. The air passes first along the outer space to the mouth of t lie bell . 



SHAW'S HOT-AIR ENGINE. 41 

and returns through the inner, forming a thin stratum in immediate con- 
tact Avith the hot wall of the furnace. 

Another axis of motion is shown at 0, of which it is the office to com- 
municate movement to the supply piston F, through the crank o, the 
connecting rod s, and the cranks t and u, which last two are fixed to the 
arbor 0, at a fixed angle to each other of seven degrees. 

The escape valve is placed at D, and kept in position by the spring d. 
A cam 1)', acting on this valve through the lever D", opens it just before 
the driving piston commences its descent at the end of the positive stroke. 

The furnace is enclosed in the iron box G, the grate bars being shown 
at g. G 7 indicates plates of iron designed to protect the walls of the 
furnace. 

In order to bring the two pistons into a favorable position for starting, 
the fly-wheel is turned on its axis; and, for the purpose of facilitating 
this operation, the arbor K is introduced, which enables the attendant 
to act on the fly by means of the clicks marked &, and the notches W. 

The furnace door I is made double to reduce loss by radiation. The 
walls of the furnace are similarly protected by means of a double envelope. 

The products of combustion escape from the furnace through the flues 
7&, protected by fire-brick, and are carried off by the chimney H. 

SHAW'S ENGINE. 

The hot-air engine of Mr. Shaw, of Boston, which was in operation in 
the park of the Exposition, received much attention, though its merits 
seem not to have been justly appreciated by the jury. This engine, 
according to the statement of the exhibitor, is of 20-horse power; but 
no particulars are given of the actual experimental trials on which 
this estimate of its capabilities is founded. Its principal parts are a 
furnace, cylindrical in form, of boiler iron, lined with refractory brick ; 
two single-acting cylinders working alternately ; and a regenerator, which 
consists of a chamber filled with tubes similar to those of a tubular boiler, 
through which the exhaust air escapes. The air is heated in the furnace 
immediately in contact with the fuel, of which it at the same time sup- 
ports the combustion. This furnace is accordingly closed air-tight, fuel 
being supplied when necessary by means of a box or receiver on the top, 
between which and the interior of the furnace communication can be 
opened ; the box itself being, in the mean time, tightly closed. From the 
furnace the air, along with the gaseous products of combustion, is admitted 
beneath the pistons of the working cylinders alternately ; and after it has 
performed its function, it is discharged through the tubes of the regen- 
erator into the chimney. The upper portions of the working cylinders 
are employed to furnish the supply of cold air from the atmosphere. 
For this purpose each piston is provided with a trunk considerably 
smaller in diameter than the cylinder ; and the annular space between 
the trunk and the cylinder, being closed in at the top, forms an air pump. 
As the piston descends, the air of the atmosphere enters this annular 



42 PARIS UNIVERSAL EXPOSITION. 

space through valves opening" inward ; and on its ascent this air is forced 
into the regenerator, where it becomes partially heated by contact with 
the tubes through which the dilated air is escaping, and thence passes 
into the furnace. 

The brick lining of the furnace is double, with a space between the 
walls : and this space the entering air from the regenerator is obliged to 
traverse before it reaches the fire. Its temperature, which is already 
somewhat raised by compression and by contact with the tubes of the 
regenerator, becomes still more elevated in its passage through this space ; 
and the additional heat which is wanted to bring up the pressure to the 
point required is supplied by the fuel. In this engine, the difficulty 
which impeded the success of most of the earlier machines of its class, 
viz., the failure to secure an adequate heating of the air, is effectually 
overcome. The heat developed by combustion is necessarily taken up 
by the air which supports the combustion, and by the gaseous products 
at the same time generated. It is not surprising, therefore, that Mr. 
Shaw has found it practicable to maintain a pressure under his pistons 
which averages about an atmosphere. But it must be observed, never- 
theless, that such a pressure can only be secured by carrying the tem- 
perature to a point which must be destructive of lubricants and of 
packing, and must increase the difficulty of preventing leaking as a 
consequence of unequal expansion. 

The construction of the engine here described will be made more clear 
by reference to the figures in Plate I. In Fig. 1 the engine is seen in 
elevation. From this will be obtained a very correct idea of its general 
appearance. Fig. 2 is a section in elevation, and Fig. 3 a horizontal sec- 
tion. Fig. 4 is a section of the regenerator. The same letters in the 
different figures are designed to indicate the same parts. A A are the 
cylinders. B indicates one of the pistons in section, and B' the corre- 
sponding trunk. C is the passage to the regenerator, and D the annular 
space forming the air pump. E is the induction valve, and F the educ- 
tion valve. M is the space beneath the grate ; X the surrounding fire- 
brick, and M' the space behind the fire-brick which the air passes through 
on its way from the regenerator to the fire. M 3 indicates the grate itself. 
E is the passage from the furnace to the cylinder, and P is the escape for 
the exhaust air. In the horizontal section the regenerator is marked V. 
The ash door is shown at /; the chamber for the supply of fuel at a. 

The engine exhibited embraced two cylinders, each single-acting, but 
acting alternately. This construction makes the power always positive. 
The dimensions as given were : diameter of the piston, twenty-four 
inches; diameter of trunk, fifteen and a half inches: length of stroke, 
eighteen inches. Available pressure, fourteen pounds to the square inch . 
IsTumber of revolutions, sixty per minute. 

With these data the power of the engine may be easily calculated. 
It was claimed to be of twenty horse power; but this is a pretty large 
over-estimate, even allowing, which is doubtful, that the asserted pressure 
of fourteen pounds per square inch can be safely employed. 



SHAW 8 HOT-AIR ENGINE. 43 

We have — 

Area of piston 452.4 square inches. 

Double this for two pistons 904.8 square inches. 

Length of stroke 1.5 foot. 

Initial pressure per square inch 14 pounds + 15 

pounds (pressure of atmosphere) 29 pounds. 

Economy requires that the pressure of the exhaust air shall not exceed 
that of the atmosphere. The induction valve must therefore be closed 
at the point proper to produce the required reduction of elasticity by the 
expansion of the confined air. This point may be found by applying 
the formula of Poisson, expressing the relation between the elastic 
force of a gas undergoing change of bulk and its corresponding volume, 
which is 






in which p and v are the original pressure and volume of the gas, and 
p Y and v L are the pressure and volnme after the change ; while y is the 
ther mo- dynamic index of the gas, or the ratio between the specific heat 
at constant pressure and the specific heat at constant volume. In the 
case of air, ^=1.421. 

The volume of the air will be equal to the product of the area of the 
piston by the distance between it and the end of the cylinder which 
forms the opposite side of the chamber within which the air is confined. 
At the end of the stroke this distance will be equal to the entire course 
of the piston, and may be represented by \. At the moment of cut- 
off, it will be the partial length of stroke which the piston has so 
far accomplished, and may be denoted by l . Then we shall have — 

i^ 
cd ? / Pi\y 



Vi ah l x \Po/ 



i i 



and hence, l = *i(^y-V =1.5 (i?-} M21 = 0.943. 

Completing the numerical operation, we find that the cut-off should 
be applied at a little short of two-thirds of the stroke. For the work 
done before the cut-off, which may be denoted by W , we have — 

W = apolo = 904.8 x 29 x 0.943 = 24,750 foot-pounds, 
which is the work of one revolution, a representing the area of both 
pistons. 1 

The work done during the dilatation of the air, which may be denoted 

x The formula given in the note on p. 31, for the theoretic case there considered, cannot 
be applied to this computation. In the present case the mechanical conditions are such as 
to require that the pressure should be constant during the second third of the stroke at least ; 
and it cannot well be greater either before or after. To assume that the pressure is con- 
stant and maximum up to the moment of the cut-off is as nearly as possible correct, and so 
far as it may be otherwise is favorable to the engine. 



44 PARIS UNIVERSAL EXPOSITION. 

by Wi, may be computed by means of an expression deduced from Pois- 
soifs formula above, viz : 

Wl= ^ f^') = 904^x 29X0.943 ^1.186-0.976^ =1 ^ m ^^ 

And if W is the total work, 

W = W + W x = 24,750 + 10,428 = 35,178 foot-pounds. 

To this are opposed three resistances, which must first be deducted 
before the available power of the engine can be known. The first is the 
resistance opposed by the air during compression, which, being analogous 
to the positive power exerted during dilatation, may be denoted by E^ 
The second is the constant resistance which takes place while the air is 
being driven into the regenerator, which maybe called E ; and the third 
is that due to atmospheric pressure upon the trunk, which we will rep- 
resent by E 2 . E and Ei are simply the inverse of W and Wi, differing 
only in proportion to the area of piston surface upon which they are 
exerted. 

And as we have — 

Double area of working piston (as before,) 901.8 square inches. 

And also, double area of trunk section 377.1 square inches. 

We haye by, subtraction, double area of annular 

section 527.1 square inches. 

So that, putting a for the first double area, and a x for the last, there 
will result the values following : 

-o «i On 

Whence R =14,426 foot-pounds and Ex =6,078 foot-pounds. Putting 
the double area of trunk section, a 2j the atmospheric resistance will be 

E 2 = 15a 2 Z = 8,191 foot-pounds, 
I being the total length of stroke. Whence, finally, 

E=E +Ri+E2=28,995 foot-pounds ; 
which deducted from 35,178, the value of W, leaves 6,183 foot-pounds as 
the balance available for work exterior to the engine during a single 
revolution. 

For sixty revolutions this becomes 360.98 foot-pounds per minute : and 
taking 33,000 foot-pounds per minute as a measure of one-horse power, we 
find the aggregate horse-power at length to be 11.24, or about eleven and a 
quarter. From this must be deducted the passive resistances, which will 
reduce the available horse-power below eleven. It is possible that a more 
rapid revolution can be maintained ; but hardly possible that the number 
can be carried up to one hundred and twenty, which woidd be necessary to 
increase the horse-power to twenty, as claimed. 

The temperature to which the air must be raised in order to secure. 
under the circumstances, a pressure of fourteen pounds to the square 
inch may also be computed. The elasticity of a gas is proportional to 



BELOU'S HOT-AIR ENGINE. 45 

its density, and to its temperature measured from the absolute zero, 
(say from — 460° F.) If the temperature of the weather at the time of 
experiment is 60° F, this will be 520° above the absolute zero. Putting 
P for the maximum pressure, p for the minimum, (that of the atmos- 
phere,) D for the maximum density, and d for the minimum 5 and, 
finally, T for the temperature at maximum pressure, and t for the 
same at minimum, we shall have, 

P TD 

p td 

The densities are inversely as the volumes ■; and the volumes are meas- 
ured by the products of the cross-sections of the spaces they occupy into 
their lengths in the direction of movement. Let these be denoted for 
the time of maximum pressure by A and L, and for that of minimum by 
a and I. Then 

D = AL d P = AM 
d al p alt 

Whence T=gJ. 

From what has gone before it appears that P = 29 pounds, p = 15 
pounds, a = 527 A square inches, A = 904.8 square inches, 1=1.5 feet, 
L = 0.943 feet, and £ = 520°. By substituting those numbers in the 
expression above, we find, 

T = 932o, and 932°— 460° == 472° F, 
which last number is the temperature to which the whole body of the 
air must be raised ; or the temperature at least which it must have in 
the cylinder. At the moment of leaving the furnace it can hardly be 
below 500° F. This determination is so high as to justify the doubt 
above expressed as to the safety, to the lubricants and packing, of attempt- 
ing to maintain so high a pressure. 

It is claimed by Mr. Shaw that his engine is more economical of fuel 
than any steam-engine; but no experimental statistics were given in sup- 
port of this assertion. The machine is however so compact and so easily 
managed as to produce a very favorable impression ; and it is to be 
hoped that the claim to economy may prove to be well founded. 

What was the actual pressure during the performance at the Exposi- 
tion could not be determined, as no manometer was observed in con- 
nection with it ; and as it was doing no work its capabilities could only 
be judged of conjectirrally. It was a very conspicuous object in the 
section of the park occupied by the United States, and was constantly 
surrounded by a crowd of interested observers. 

BELOU'S ENGINE. 

Mr. Shaw is not the only inventor who has sought to avail himself of 
the very effectual mode above described of securing the thorough heat- 
ing of air. A patent was taken out in 1860 by Mr. Belou, a French engi- 



46 PARIS UNIVERSAL EXPOSLTIOX. 

lieer, for an engine of which the motive power was obtained in the same 
manner, but which differed from Mr. Shaw's in several particulars. In 
the hist place, it employed but one working cylinder, of which the ins- 
ton was double-acting. It had, secondly, an independent supply pump, 
also double-acting 5 and it differed, thirdly, from Mr. Shaw's engine, 
in having no regenerator. The working cylinder was, however, provided 
with a jacket, between which and the cylinder itself the air circulated 
in passing from the supply pump to the furnace ; becoming thus par- 
tially heated. 

As Mr. Belou's engine has been subjected to careful tests of its per- 
formance in regard to economy, conducted by Mr. Tresca, the able sub- 
director of the Conservatoire des Arts et Metiers, it may be interesting, in 
the absence of corresponding data in regard to the engine of Mr. Shaw, 
to present here the results. The first trial was made on an engine of very 
nearly four horse-power, as determined by a Prony dynamometer. The 
consumption of coal per horse-power amounted to 2.61 kilograms per 
hour. It appeared, however, from the indications of the pressure-gauge, 
that the actual power developed in the cylinder amounted to more than 
five times as much, or to twenty-two-horse power. 

From a careful determination of the sources of loss, it was shown that 
more than forty-four per cent, of the whole power was expended in over- 
coming passive resistances, and thirty-three and a half per cent, in com- 
pressing the air for the supply — there remaining only about twenty-two 
per cent, available for use. By a series of observations on the tem- 
perature of the escaping air, it was further found that about one-half 
of the heat developed by the combustion of the fuel was lost without 
any effect at all. These experiments were made in Paris in 1801. 

In 1866 a much more powerful engine by the same inventor was sub- 
jected to a series of experiments by Messrs. Tresca and Alcan, in a paper 
manufactory at Cusset, of which it had been erected as the driving- 
power. The working cylinder of this engine had a capacity of about eighty 
cubic feet ; that of the supply cylinder was about half as great. In this 
case the amount of force developed, as measured by the indications of 
the manometer, was equal to one hundred and twenty-horse power, but of 
this the supply absorbed eighty-horse power, or two-thirds of the whole : 
and more than ten-horsepower was estimated to be necessary to overcome 
the passive resistances. Less than thirty-horse power, therefore, or one- 
quarter of the whole, was actually utilized. The consumption of coal was 
about forty kilograms per hour : or, according to the calculation of the ex- 
perimenters, 1.16 kilograms (three pounds) per horse-power per hour. 
This performance places the engine about upon a par with an economical 
steam-engine. It is to be observed, however, that the heat was carried to 
a height which could not but tend to deteriorate rapidly the parts of the 
engine exposed to it; and especially the interior of the working cylinder. 
In order to protect this surface, it was constantly lubricated with a 
solution of soap in water, of which about five gallons were consumed 



ECONOMY OF HOT-AIR ENGINES. 47 

per hour. The great heat imparted to the air rendered inevitable also 
a very large final loss. It was made evident by very eonclusive experi- 
ments that the air in the chimney was at least 250° Centigrade (450° 
Fahrenheit) above the temperature of the atmosphere, and it is com- 
puted by Mr. Tresca that fully seven-eighths of the heat produced by 
the fuel was expended unproductively. 

Notwithstanding this, the fact that the engine, after all, performed as 
economically as the best steam-engines, is eminently encouraging to 
those who hope to see steain-power advantageously replaced by some- 
thing safer and more universally available. This view is taken in an 
interesting paper presented to the Academy of Sciences of France by 
Messrs. Burdin and Bourget in the year 1863. The paper here referred to 
maintains the practicability of carrying the heat in an air-engine to a very 
high temperature, and of securing such a temperature by a very econom- 
ical process of heating. It is proposed to heat the air in a furnace, but 
not in contact with the fuel, by means of an assemblage of tubes passing 
through the fire. Various expedients are suggested for securing the 
parts of the engine which are exposed to high heats, or for protecting 
against their injurious effects ; and it is supposed that the temperature 
of the air may be raised advantageously as high as 600° Centigrade. It 
is at the same time admitted that one-half of the heat of the fire will 
escape directly through the chimney. 

With these data the authors present a series of calculations founded 
upon formulae derived from the mechanical theory of heat, by which it 
would appear that heated air ought not to require, in a properly con- 
structed engine, more than one-third of a kilogram of coal per horse- 
power per hour. This economy, however, is yet far from being realized ; 
and the disadvantages attendant on the use of extremely high tempera- 
tures, some of which have been mentioned above, make it very improb- 
able that it ever will be. 

Mr. Shaw's engine ought to be more economical of heat than that of 
Mr. Belou, inasmuch as the regenerator must save a considerable por- 
tion of the excess of heat of the escaping air. The claim of its inventor, 
that its consumption of fuel is less per horse-power per hour than that 
of the best steam-engine, may possibly be well founded. 

Mr. Belou's engine is represented in Plate II, Figs. 1 and 2. The first 
is a general plan of the machine, and the second a vertical section passing 
through the axes of the two cylinders. 

A marks the furnace or fire-box, at the extremity of which is seen the 
hopper, or receptacle for fuel, marked B. 

The working cylinder is represented at D, and the supply cylinder 
atE. 

The air, in passing from E to the furnace, passes through the space d 
between the working cylinder and its enveloping jacket. Provision is 
made by which a portion of the air, larger or smaller, as occasion may 
require, may be made to pass into the furnace over the fuel, and not 



48 PARIS UNIVERSAL EXPOSITION. 

through it. By this means the intensity of the heat may be varied, and 
the working- pressure increased or diminished. 

M is the main shaft, N" the fly- wheel, and Q Q' connecting rods which 
explain themselves. The fly-wheel on the large engine at Cusset weighs 
about fifteen tons. 

The fuel introduced into B is spread over the grate by a mechanical 
contrivance operated by the arbor B 7 , which is connected with an eccen- 
tric on the main shaft. 

The small machine, first made the subject of experiment by Mr. Tresca, 
was provided with a reservoir for containing a reserve of compressed air 
to be employed in starting the machine ; for, every air-engine, whether 
double or single acting, has to contend with a resistance exceeding the 
power during a portion of the stroke. The machine at Cusset was with- 
out such an auxiliary, but was put in motion by means of a turbine of 
fifty-horse power, which was employed to drive it for a few revolutions, 
after which it regulated itself. The trouble of starting is one of the dis- 
advantages of all motors of this class. When the power is small the 
fly-wheel may be turned by hand, or by some mechanical contrivance, 
such as is provided in Mr. Ericsson's engine ; but when it is comparable 
to that of the great engine at Cusset a reserve is necessary. This may 
be furnished by a reservoir of condensed air, provided very great care 
be taken to prevent leakage. The experience of the engineers engaged 
in constructing the tunnel under the Alps shows that air under heavy 
pressure may be kept for weeks in metallic reservoirs without sensible 
loss. The experience of Mr. Belou seems to have been different, since 
after having adopted this expedient he abandoned it for another. 

The observations do not show the maximum temperature which was 
imparted to the air; but the fact that the exhaust at the top of the 
chimney was at 250° Centigrade, (482° Fahrenheit.) shows that it must 
have been excessive. The mean pressure was not, however, very great. 
The induction valve was closed at four-tenths, and the air acted expan- 
sively through the remainder of the stroke, the pressure falling to equality 
with that of the atmosphere at the end. 

We must conclude, upon the whole, that in this machine, it is practi- 
cally demonstrated, not only that heated air can be made successfully a 
source of motive power, but also that this can be done economically and 
upon a large scale. As being the first in which these several proposi- 
tions have been fully established, this engine cannot but be regarded 
with peculiar interest. 

roper's engine. 

In the American annex was exhibited a hot-air engine by Messrs. 
Crosby, Butterfielcl and Haven, of Xew York, under The name of 
Roper's engine. This was not at any time in operation, nor was there 
any attendant present to explain its peculiarities, although it was the 
subject of a good many inquiries on the part of visitors. Its principal 



ROPER'S HOT-AIR ENGINE. 



49 



organs were, however, sufficiently recognizable, and the compactness of 
its arrangements appeared to be such as to adapt it very advantageously 
to small industrial operations. The furnace in this engine is a cast-iron 
cylinder lined with fire-brick. Immediately over the furnace, and 
apparently formed in the same casting, is the working cylinder, smaller 
in diameter than the furnace and open above. The piston rod is kept 
vertical by means of a guide, and two connecting rods attached to the 
piston, one on each side of the proper piston-rod, are attached to balance 
levers which are united at their opposite ends by a cross-bar, to the 
middle of which is attached the connecting rod which turns the crank 
of the main shaft. The balance levers are pivoted in supports which 
are secured to the working cylinder itself, and they carry, also, a pair of 
rods which operate the piston of the supply cylinder. The supply cyl- 
inder is immediately under the working shaft, and is as conveniently 
near the furnace as practicable, standing upon the same base with it. 
The furnace is air-tight, and the air supply is forced into it beneath the 

Fig. 2. 




ROPER'S HOT-AIR ENGINE. 



grate, passing through the fuel, and so upward into the working cylin- 
der. Provision is said to be made to divide the air current in such a 
4 i A 



50 PARIS UNIVERSAL EXPOSITION. 

manner as to allow a portion of it, at pleasure, to enter the furnace 
above the fuel, for the purpose of regulating the rapidity of combustion 
and the temperature of the charge in the cylinder, but the contrivance 
by which this is effected was not exactly understood. The exhaust air 
with the products of combustion is discharged through a pipe commu- 
nicating with the chimney of the building. The main shaft carries a 
heavy fly-wheel to maintain the motion during the downward stroke and 
dmiug the period of greatest compression of the supply. The same 
shaft carries a pulley by which the power is applied. The whole machine 
occupied on the ground a space of about five or six feet square. The 
power could not be ascertained. 

An engine so similar to this as apparently to be identical with it was 
seen in London after the Exposition, where it is sold by the manufac- 
turers, Edwards & Co., of Oxford street, as their own invention. This 
is shown in Fig. 2. 

The cylindrical furnace is indicated by the letter A. At B is seen the 
supply cylinder. C is the fly- wheel, D the working cylinder, and E the 
escape pipe. F is a governor which acts upon the valves in the inte- 
rior by means of levers, cams, and rods, indicated in the figure, and of 
which the effect is to vary the quantity of air passing through the fuel, 
and to cause a greater or less portion of it to enter the furnace above. 

The manufacturers say that this engine is intended to be used only 
with anthracite coal. With a consumption of eight pounds of coal per 
hour its performance is equal to three-horse power. 

^so provision is here made for introducing the fuel while the engine is 
in operation. Interruptions will therefore occur from time to time in 
order to replenish the fire 5 but these, it is stated, will not consume more 
than twenty minutes during a working day of ten hours. In starting the 
machine it is necessary, as in the use of the engines previously described, 
to turn the fly-wheel for a few revolutions by hand. And it is also neces- 
sary that the fire shall be well lighted before the door of the ash-pit is 
closed. 

The peculiar merit of this engine is such an arrangement of parts as to 
reduce the bulk to a minimum. In order to accomplish this the regen- 
erator is excluded, and no attempt is made to secure a partial heating of 
the supply, as in the Belou engine, by causing it to circulate in contact 
with the heated walls before entering the furnace. The statement s there- 
fore in regard to the consumption of fuel per horse-power are remarkable : 
and it is to be desired that some careful experimental determinations 
should be made of the actual performance, as tested by the dynamometer, 
in order to verify their accuracy. 

LAUBEEAE'S ENGINE. 

The only engine present in the Exposition constructed on the principle 
of the displacement of a body of confined air which, without being dis- 
charged, is subjected to alternate extremes of cold and heat, was exhibited 



LAUBERAtj's HOT-AIR ENGINE. 51 

by Mr. Lauberau, an inventor of Paris. In this machine a certain volume 
of air is enclosed in a cylinder of metal, in which there is also a large 
moving plunger which, by occupying alternately one end and the other 
of the cylinder, drives the air in like manner in the opposite direction. 
The upper portion of the cylinder is surrounded by a jacket, between 
which and the cylinder itself there is maintained a constant circulation 
of cold water. The design of this is to absorb the heat which the air may 
bring with it, when, by the descent of the plunger, it is forced to enter 
this space. As the plunger itself is but slightly less in diameter than the 
interior of the cylinder, the air during the transfer is reduced to a thin 
cylindrical stratum, and is brought into close contact with the cold walls. 
The effect of the engine depends as much upon the efficiency of this cool- 
ing process as upon the subsequent heating, and therefore it is desirable 
that the water of refrigeration should be as cold as possible. But as this 
water must necessarily be drawn from natural sources, it is obvious that 
the engine will be more efficient in winter than in summer. 

The lower portion of the cylinder is occupied by a furnace which, in all 
material respects, resembles the furnace of the Ericsson engine already 
described ; that is to say, it is a cylinder, smaller than the air cylinder, 
leaving an annular space between its walls and those of the latter. The 
plunger also, like the piston plunger of the Ericsson engine, is provided 
with a bell- shaped continuation, which enters the annular space around 
the furnace. If ive suppose the plunger in the lowest position it can 
occupy, that is in the end next to the furnace, the air will be in the upper 
end of the cylinder, and in contact with the walls which are kept cold by 
the water circulating around it. As the plunger rises, the air, being com- 
pressed, seeks to escape, and is forced to pass down the annular space 
between the bell and the outer wall of the cylinder at bottom, and after- 
wards up between the same bell and the hot walls of the furnace. It thus 
becomes rapidly heated, and its pressure rises ; but this does not affect the 
motion of the plunger, which is pressed equally above and below. The 
pressure is utilized by means of a second and smaller cylinder, provided with 
a piston which is connected with the crank of a working shaft. The lower 
part of this cylinder communicates with the heated extremity of the air 
cylinder. The air expanding under the influence of the heat, passes into 
the small cylinder and raises its piston. When the plunger descends, 
the effects are the reverse of those just described. The air is driven into 
the cold end of the cylinder and contracted by cooling, and the piston of 
the working cylinder also descends. It is understood of course that the 
movements of the plunger are determined by those of the working piston ; 
and as this piston is single acting, during one-half of the revolution the 
machine exerts no power. It must therefore be started by turning the 
fly-wheel once or twice by hand. After that, if the heat is up in the fur- 
nace, it will continue to act without further attention. The circulation 
of cold water is kept up by means of a pump which derives its force from 
the working shaft. In the very small models constructed by Mr. Lau- 



52 PARIS UNIVERSAL EXPOSITION. 

berau, of less than one-half-horse power, this puuip is very simple, being 
merely a small round box into which a solid plunger enters through a 
stuffing box. 1 In the larger, the refrigerating part of the cylinder, as 
well as the heating, is furnished with an annular extension, while the 
plunger displacer carries a bell at each end. In these also an economy 
of heat is secured in the construction of the furnace, by giving it an exte- 
rior wall between which and the surface to be heated the flame and 
gaseous products of combustion are forced to circulate on their way to 
the chimney. Two working cylinders have also been employed instead 
of one, by means of which a more equal performance is maintained, and 
the weight of the fly-wheel is reduced. 

This engine, which seems admirably adapted to small industries 
requiring but a fraction of a single horse-power, is not, however, very 
economical. From experiments made at the Conservatoire rfes Arts et 
Metiers, in 1863, upon a Lauberau engine of four-fifths of one-horse 
power, it was found that the consumption of coal was equal to l.oo kilo- 
grams (nine or ten pounds) per horse-power per hour, while the refrige- 
ration required 700 kilograms (180 gallons) of water per hour also. It 
is not to be understood, however, that this great quantity of water has 
to be constantly renewed, or that it must be necessarily suffered to run 
to waste. If the quantity is sufficient to allow some interval between 
its discharge from the refrigerator and its return to the refrigerator 
again, it will be brought back, by natural cooling, to a temperature suffi- 
ciently low to allow of its repeated use. 

This machine, though not abstractly economical, may in certain cir- 
cumstances be practically so. It is adapted, better than any other thus 
far presented, to domestic uses for which very small power is required, 
as it is portable and compact, and can run by means of a gas lamp very 
well. Though it will not work so cheaply as a steam-engine, it may per- 
form certain tasks more cheaply a great deal than human labor could do. 
and it may thus be a source of a relative economy which is very real. 

The Lauberau engine which was the subject of the experiments of 
Mr. Tresca, is represented in Plate II. Figs. 3. 1. 5 and 0. Fig. (3 is a 
vertical section made through the axis of the displacement cylinder. 
Fig. 4 is a general plan. Fig. 5 is a cross-section exhibiting the details 
of the working cylinder and of the furnace. 

A is the working cylinder with the working piston a, acting on the 
arbor G by means of the connecting rod g and the crank g 1 . 

BB' is the displacement cylinder, and b the plunger. The plunger is 
formed of non-conducting material, and carrries at its two extremities 
the bell-shape i or cylindrical prolongations which enter the annular 
spaces V and &". This piston is acted on by the connecting rods H 
and h. A roller, or friction wheel, r, sust ains the weight of the piston 

^n some models this feed pump is more simple still, being merely a little metallic cup. 
closed by a membrane of caoutchouc, which being attached by its middle point to a rod 
moved by a little crank, rises and falls with a movemeLt resembling the beating of the heart. 



WILCOX'S HOT-AIR ENGINE. 53 

and its connections during the movement. This turns on its axis in a 
closed cavity communicating with the cylinder at the point of support 
only. 

C is the furnace, with a grate adapted to coke or charcoal. A flue is 
indicated by the letter c, in which the gaseous products of combustion 
may circulate around the annular space b' before escaping by the chim- 
ney. The air, in passing from one end of the cylinder BB' to the other, 
takes necessarily always the annular spaces 1)' and W in its course. 

F is a tube which permits free communication constantly between the 
displacement cylinder B B' and the working cylinder A through the 
annular space V. 

E is the chimney provided with a damper, e. 

GG' are furnace doors for introducing fuel and regulating the draught. 

V is the fly-wheel. 

K is the tube through which the water of refrigeration is introduced 
within the jacket surrounding the cold end of the displacement cylinder, 
and K' the passage of escape for the water after having circulated 
through this space. 

M is a lever serving to enable the attendant to open the valve m, which 
establishes communication between the cylinders and the atmosphere. 

Finally, n is a suifting valve opening into the cold extremity, by which 
the loss of air by escape through the packings is compensated. 

In the small engines on this plan the displacement cylinder is vertical, 
and a powerful gas lamp takes the place of the grate. A representation 
of one of these is given in section in Fig, 6. A is the working cylin- 
der; B, the working piston; D, the piston displacer; E, the furnace 
space, showing the section of the gas-burner; F, the cold-water jacket. 
The other parts will explain themselves. The products of combustion 
pass downward between the wall of the furnace and the inner wall of the 
annular cavity in which the air is heated, and pass off through a flue 
opening toward the left in the figure, beneath the working cylinder. 
Some of these machines are hardly a cubic foot in dimensions, and they 
vary in power from a sixth to a thirtieth of a horse-power. Their neat- 
ness and portability are very much in their favor, as well as the extreme 
promptness and facility with which they are set to work. One of the 
most amusing displays during the early days of the Exposition was a 
little boat, six or eight feet long, which ran along the shore of the Seine, 
in front of the Champ de Mars, driven by a Lauberau engine of perhaps 
an eighth of a horse-power. It was too small to carry a passenger, but 
made its trips from point to point, according as it was directed by the 
attendant. 

WILCOX'S ENGINE. 

The foregoing enumeration embraces all the hot-air engines presented 
at this Exposition. There was one from the United States exhibited at 
London in 1862, which was esteemed there worthy of a medal, and which 



54 PARIS UNIVERSAL EXPOSITION. 

was distinguished by some peculiarities deserving of notice, by way of 
comparison with those above described. This was the Wilcox engine, 
of which the peculiarity consisted in the employment of two working 
cylinders through which the air successively passed. The furnace was in 
the lower portion of one of these cylinders, and the supply pump was in 
the upper chamber of the same cylinder. The engine was further pro- 
vided with a regenerator of thin metal plates. The air, after being coin- 
pressed in the supply pump, passed through the regenerator, taking up 
the heat left there by the last charge of escaping air, and thence into 
the second working cylinder. In this it produced a partial effect, due to 
the heat already absorbed, and then entered the first or principal work- 
ing cylinder, where it received the heat of the furnace. The advantage 
of admitting the supply air to the cylinder which contains the furnace is 
very considerable, as it tends to prevent that cylinder from being over- 
heated, while it utilizes the heat which would otherwise be injurious. 

franchot's engine. 

Another machine was exhibited in model, in 1855, at Paris, so inge- 
nious in its conception that it has been made the subject of an elaborate 
theoretic discussion by Mr. Combes, of the Imperial School of Mines, in 
his excellent work on the mechanical theory of heat. This was the 
invention of Mr. Franchot, of Paris. It consisted of two cylinders, 
entirely equal, and both of double effect, of which the pistons were con- 
nected with cranks on the same working shaft. One of these cylinders 
was to be kept constantly at the maximum temperature, and the other 
at the temperature of the ambient air. The mode of maintaining the 
superior temperature was not perhaps satisfactorily settled, since Mr. 
Franchot has never executed his project on a large scale. Between the 
two cylinders communication was always free, both above and below 
their respective pistons ; the air passing from one to the other alter- 
nately, as the pistons moved. But the body of air above the pistons 
was permanently separated from that below them. These two bodies 
of air, therefore, having been originally equal in mass, always remained 
so, though their volumes were constantly changing. Regenerators were 
placed both at top and bottom, in the space through which the air had to 
pass in its passage from cylinder to cylinder. In these regenerators it 
was designed that the air should leave its heat in passing from the hot 
cylinder to the cold; and it was presumed that it would take the same 
heat up again, in its return from the cold cylinder to the hot. Finally. 
in the attachment of the pistons to the working shaft, the arrangement 
was such that the crank of the hot cylinder piston was always ninety 
degrees, in the direction of revolution, in advance of the other. By con- 
sidering the movements of the piston under these circumstances, we may 
easily discover what must be the maxima and minima of the effective force 
of the engine, and the progress of the fluctuations of the force. For con- 
venience, let the piston of the hot cylinder be called A. and the other B. 



franchot's hot-air engine. 55 

Then if A is in the middle of its course, descending, B will be at the 
uppermost limit of its course, and about to descend. All the superior 
mass of air will be in the cylinder A, and in the upper regenerator ; and, 
disregarding the regenerator, we may say that it is reduced to one- 
half its normal bulk. By the law of Mariotte, its pressure would be 
doubled; but by the added effect of the elevated temperature which, 
for facility of illustration, we will suppose to be sufficient to double its 
elasticity, it will be quadrupled ; so that, at the instant in which B begins 
to descend, there will be a downward pressure on both pistons of four 
atmospheres. At the same time the inferior mass of air will be expanded 
to once and a half its normal bulk, and its pressure would be equal to two- 
thirds of an atmosphere only, but for the high temperature of the part 
which occupies the lower half of the cylinder A. The actual inferior 
pressure will be something more than four-fifths of an atmosphere, and 
the excess of downward over upward pressure will be upward of three 
atmospheres. At this time, however, the motion of the piston A is 
much more rapid than that of piston B, so that the downward pressure 
will rapidly diminish, and the upward pressure increase. When the revo- 
lution has advanced sixty degrees from the position first considered, or 
when the crank of A is one hundred and fifty degrees from the vertical, the 
two pressures will balance ; and when the piston A reaches its lower liinit, 
the piston B being then at the middle of its course, the inferior body of air 
will occupy half its normal space in the lower half of the cylinder B, while 
the superior mass will fill the entire cylinder A, and half the cylinder B 
also. The upward pressure will now be two atmospheres, and the down- 
ward pressure less than two. During the preceding thirty degrees of revo- 
lution, therefore, the effective force of the engine will have been nega- 
tive, and the same will continue to be the case until the crank A shall 
have passed forty-five degrees beyond its lowest point, or two hundred 
and twenty degrees from the vertical. The two cranks will then be 
equally inclined to the vertical on opposite sides of it, and their efforts 
to turn the shaft will be opposed to each other. These efforts being 
necessarily equal, and acting at equal distances from the centre of 
motion, will neutralize each other, and, for a moment, the effective 
force will be zero. When the piston B reaches the bottom, and the 
piston A is half advanced upward, the circumstances are the same 
mechanically as those with which the movement commenced, only now 
it is the inferior mass of air which is compressed into half its normal 
bulk in the hot cylinder, while the superior mass is dilated into once and 
a half the same bulk. It is further evident that this position is not 
that in which the difference of bulk of the two masses is absolutely the 
greatest, though it is here that the effective force is maximum; for, 
owing to the greater rapidity of movement of that piston which is nearest 
the middle of its course, it will be evident that, while the piston B is 
approaching the limit of the stroke, and the piston A receding from it, 
the volume of the inferior mass of air is, on the whole, enlarging, so 
that the point of minimum volume must occur before the completion 



5G PARIS UNIVERSAL EXPOSITION. 

of the stroke of B. It actually occurs for the two bodies of air alter- 
nately, when the crank B is within thirty degrees of its culminations, 
upper or lower, and approaching them. This machine, if it could be 
realized, would possess two important advantages. 

In the first place, its negative effect, or total active resistance, instead 
of consuming, as is usual in air-engines, two-thirds of the positive power, 
amounts to less than one-third. In the second place, it admits of increase 
of power without increase of dimensions, by the simple expedient of con- 
densing the air within the cylinder in advance. In this ease, indeed, 
some leakage might occur; but compensation for such a leakage could 
be provided without a great expenditure of force. In the third place, it 
gives, theoretically, the largest amount of work for the heat expended 
that it is practicable under any form to attain. But all these advantages 
are dependent for their realization upon the efficiency of the heating 
apparatus and the satisfactory performance of the regenerators. It 
encounters here the same difficulties which have impeded as yet the 
complete success of every form of hot-air engine. 

II.— INFLAMMABLE GAS-EXGIXES. 

The enormous force developed in the explosion of gunpowder could 
hardly fail early to occupy the minds of the ingenious, with the effort to 
make it available for the uses of industry. Accordingly, we find that 
this problem formed a subject of study with such men as d'Hautfeuille. 
Huyghens, and Papin. But the intense energy of the force and the sud- 
denness of its action seem to have discouraged the attempt to apply it 
directly as a motive power. The earlier experimenters occupied them- 
selves with the endeavor to turn it to account by indirect means. The 
expedient which appeared to them most promising was to use it for the 
purpose of creating a vacuum. In fact, if a comparatively small charge 
of gunpowder be exploded in a closed vessel furnished with valves freely 
opening outward, the enormous expansion of the gaseous products of the 
explosion, an expansion due to the excessive heat developed, will drive 
out the atmospheric air through the valves, while the gases, contracting 
almost as suddenly as they expanded, will leave the vessel nearly void. 
It was first proposed to apply this principle to the elevation of water. 
A very simple apparatus suffices for this purpose. Let there be placed. 
for instance, such a vessel as has just been supposed, some fifteen or 
twenty feet above the level of a reservoir; a tube, open at both ends, 
communicating between this vessel and the reservoir will be all that is 
needed. So soon as the air has been expelled from the vessel by whatever 
means, the water of the reservoir will rise under the pressure of the 
atmosphere and occupy its place. This water may then be discharged 
at the superior level, and the apparatus will be ready tor the repetition 
of the operation. In order to prevent the return of the water to the 
reservoir, when the orifices of discharge of the upper vessel are opened. 
the tube may have valves in it opening upward but closing under a down- 
ward pressure, or, what is simpler, it may be recurved at the upper 



INFLAMMABLE GAS-ENGINES —EARLY EFFORTS. 57 

extremity and enter the explosion chamber by the top. Such was the 
application of this power suggested by d'Hautfeuille. Huyghens per- 
ceived that it was capable of being turned to more varied uses. He pro- 
posed to employ a cylinder with a movable but air-tight piston to serve 
as an explosion chamber, with a view to obtain a reciprocating motion. 
In fact, by blowing out the air contained in' such a cylinder through 
valves properly disposed, the atmospheric pressure could be made to force 
the piston downward, and thus indirectly to move the arm of a lever to 
raise a weight or to turn a crank. The valves suggested and perhaps 
actually used by Huyghens for this purpose were sufficiently rude. They 
were nothing more than open but flexible leather tubes, which, after 
allowing the air to escape, were expected to collapse under the pressure 
from without, and prevent it from re-entering. Papin substituted for 
these a much more efficient and neater contrivance. This was to make 
an opening in the middle of the piston sufficiently large for the free escape 
of the air, and to cover this with a bell. The bell, yielding to the upward 
pressure, permitted the air to pass out, but, dropping immediately after 
into its place, effectually prevented its return. But none of these expe- 
dients sufficed to make a practically useful gunpowder engine. 

In 1791, John Barber, a British inventor, patented a project for a 
new motive power, which may perhaps be regarded as embracing the 
germ idea of the modern imflaminable-gas engine. This project, how- 
ever, for it amounted to no more, was of the crudest sort. The motive 
force was to be derived from the direct action of a powerful current of 
flame, which he proposed to create by the combustion of inflammable gas 
mingled in explosive proportions with common air. The gas was to be 
generated by the destructive distillation of any combustible substances 
in a tight vessel. From the generator it was to be conducted into another 
chamber, called the "explosion chamber," common air being simulta- 
neously introduced into the same vessel by a different channel. Under 
such circumstances combustion would of course be explosive, generating 
a powerfully outrushing stream of flame, which might be maintained as 
long as the gas should continue to be supplied. As the plan was to 
employ only the " vis viva 11 of this stream to turn a wheel or a windmill, 
the unpractical nature of the scheme needs not to be pointed out. 

In 1794, another British inventor, by name Robert Street, patented a 
gas engine, founded on principles somewhat more rational than those 
which seem to have guided Barber, inasmuch as he clearly enough per- 
ceived that if heated gas is to be made the medium of applying mechan- 
ical power, it is through its elasticity, and not through the momentum of 
its mass, that we must expect to see the useful effect produced. But 
inasmuch as Street proposed to make the cylinder of the engine itself the 
generator of the gas by which the engine was to be driven, his scheme 
in a practical point of view w^as not a whit less visionary than that of 
Barber. 

These early and, as they seem to us now, absurd projects, though they 
bore no fruit, and were probably never even subjected to a serious experi- 



58 PARIS UNIVERSAL EXPOSITION. 

mental test, deserve mention in the history of this subject, as marking 
the progress of an idea destined at length to be successfully; wrought out. 
Indeed, considered as an idea merely, it was successfully wrought out 
only a few years later. The gas engine, in every essential particular, 
such as it is at the present time, that is to say, actually realized in a 
form available for purposes of industry, was invented as early as 1799. 
and patented in France by an ingenious artisan, named Lebon. Never- 
theless, this machine was not a success. It attracted no notice in the 
scientific world, and inspired no confidence in the industrial. After the 
lapse of about half a century it was reinvented, and reinvented, doubt- 
less, quite independently ; the resemblance of the modern machine to that 
of Lebon being so complete that a description of one of them might 
easily be supposed to have been taken from the other. At the date of 
Lebon's invention illuminating gas had not yet come into general public 
use, but the mode in which he proposed to prepare the gas for his engine 
was precisely that which is now in universal use in the works of the 
great city gas companies. Having thus provided himself with a suffi- 
cient reservoir of this essential material, his plan was to introduce a certain 
charge of this into the cylinder of his engine beneath the piston, and 
simultaneously through another channel to admit a proper proportion of 
atmospheric air. The mixed gases were then to be exploded by means 
of the electric spark, their consequent dilatation furnishing the desired 
motive power. The inventor seems to have overlooked no provision 
necessary to secure the perfect success of his plan. The engine was 
entirely self-regulating. It operated two pumps, one of them designed 
to introduce the supply of gas, and the other that of air. Accord- 
ing to the descriptions, by which only we know it, it would seem to 
have combined every feature important to secure success, and yet, as 
already stated, it was not successful. Its failure is probably to be 
attributed to the influence of several causes, which, in the progress 
of improvement in the industrial arts, and the simultaneous advance- 
ment of experimental science, have since ceased to exist. In the 
first place, as just remarked, inflammable gas had not yet been intro- 
duced for purposes of general illumination; and the preparation of gas 
for the engine must have been troublesome and disproportionate expen- 
sive. Electrical science, moreover, had not then reached such a state of 
perfection as to be in condition to suggest an apparatus for producing 
the spark required to inflame the gases, capable of operating with the 
unvarying certainty indispensable in such a machine: and finally, the 
mechanic arts were probably yet unequal to the requisitions of a problem 
involving the peculiar difficulties which the construction of this engine 
presented. In point of fact it can hardly be doubted that mechanical 
difficulties were among the principal obstacles which prevented the full 
realization of a project which, abstractly considered, seems to have been 
entirely feasible. Many other inventors since Lebon. have occupied them- 
selves with gas engines. Until within the past ten years, none have 
succeeded in establishing their inventions in the confidence of the indus- 



INFLAMMABLE GAS-ENGINES — JOHNSON'S. 59 

trial world. Of machines of this class which have left no trace except 
in history, it is unnecessary here to speak with minute detail. There is 
one of them, however, which deserves a passing- mention, as having 
been distinguished from the rest by a feature which may be character- 
ized as more bold than practical. This consisted in the proposed sub- 
stitution of oxygen gas instead of atmospheric air in forming the 
explosive mixture by which the piston was to be driven, and hydrogen 
instead of coal-gas; the proportion being that required to form water 
by combination ; so that after explosion the vacuum of the cylinder might 
be complete. It is true that immediately after the explosion, the water 
of combination would exist in the state of vapor, and that this would 
have a momentary elasticity so great as, by its direct action, to drive 
the piston to the end of the cylinder. But this vapor would be almost 
instantaneously condensed, especially if the cylinder were kept properly 
cooled; and a vacuum being thus formed practically perfect, the piston, 
on the opening of the valves for the admission of a new charge of gas 
to the opposite side, would be urged by the full pressure of the atmo- 
sphere upon its entire surface. If this idea could be practically realized, 
it would certainly be attended with very sensible advantage. In the 
gas-engine as now constructed, there is necessarily a period during each 
stroke in wmich the effective force is zero. This is the case during a 
great part of the time of admission of each successive charge of gas, 
which continues for one-half the length of the stroke. If during all this 
time there should be a vacuum in the opposite end of the cylinder, the 
engine, instead of being powerless, would be actuated by a positive 
working force upon the piston equal to one atmosphere; an advantage 
which more than doubles the efficiency as yet secured in any motor of 
this class. The project here described was patented by James Johnson, 
a British inventor, in 1841. 

Mr. Tresca, in an interesting article published in the Annals of the 
Conservatoire, has expressed surprise that subsequent inventors have 
not occupied themselves more with this idea of Johnson. But in point 
of fact, the plan is much more plausible than feasible. To say nothing 
of the trouble and expense of generating the gases, which in the case 
of oxygen, especially, would be sufficient to defeat the economical object, 
the violence of detonation of the pure gases in the proportions suggested 
would be such as to endanger the safety of the machine, or to render 
the power unmanageable. It is also perhaps questionable whether, in 
practice, the condensation could be determined so as to take place at 
the moment desired. If the piston were free to take on the velocity of 
a projectile discharged from a gun, no doubt the pressure would follow 
it to the end; but if, owing to the connections by which the force is to 
be utilized, the motion of the piston is comparatively slow, the collapse 
may occur before it reaches the limit of its course. In such a case, the 
vacuum would be injurious. In order to reduce the violence of the 
explosion, the quantity of gas employed in each charge might be dimin- 
ished, and the charge might be allowed to dilate to some extent, as it 



60 PARIS UNIVERSAL EXPOSITION. 

would naturally do in consequence of the movement of the piston, before 
being" fired. But these expedients would reduce correspondingly both 
the direct effect of the gas, and the indirect effect of the vacuum which 
it is sought to utilize. It is not very surprising, therefore, considering 
all the difficulties in the way, that no successful gas-engine has yet been 
constructed, deriving its power from the explosion of hydrogen with 
oxygen. 

Three engines present themselves in the present Exposition which 
derive their force from the combustion of inflammable gas. Two of these 
employ the direct pressure of the gases as dilated by combustion. The 
third reverts to the principle which chiefly occupied the earlier inventors, 
viz : that of using the gases only as a means of clearing the cylinder of 
air, and rendering available the pressure of the atmosphere. It is to 
this last, which, though not earliest in the order of invention, revives 
the idea which belongs to the earlier period of this history, that atten- 
tion will be first directed. This prominence of position may also be con- 
sidered as due to this machine, since it was rewarded by the jury with 
a gold medal, while the other two just mentioned received a less honor- 
able distinction. 

OTTO & LANGEN'S OAS-ENGTXE. 

This machine is a Prussian invention, exposed by Messrs. Langen & 
Otto, of Cologne. Externally, it presents the appearance of a doric 
column something more than a metre in height, upon the enlarged capital 
of which is fixed a horizontal plate, which supports the arbor of the 
fly-wheel and other parts of the machinery. This column is the working 
cylinder. The mixed gases — common coal gas and air — are introduced 
at its base, and fired by an ingenious mode of communication with a gas 
jet, which is constantly burning. The base is surrounded by a jacket. 
between which and the cylinder itself cold water is always circulating, 
to prevent too great elevation of temperature. By the explosion of the 
gas, the piston, which has some weight, is driven to the top of the cyl 
inder. The collapse which immediately follows produces a vacuum, or 
an approach to a vacuum, beneath the piston : and this now descends, 
urged by the pressure of the atmosphere with its own weight super- 
added. In order to transfer this force to the working arbor of the 
machine, the piston-rod is, on one side, provided with a rack, which acts 
on a spur wheel on the arbor. This wheel is loose upon the arbor, but 
is free to turn in one direction only ; that is, in the direction which cor- 
responds to the rising of the piston. In the descent, a ratchet and catch 
prevent its turning except as it turns the arbor with it. There are two 
tall uprights, one on each side of the piston-rod, which serve as its guides- 
and give stability to the machine. A second gear-wheel on the working 
arbor turns a similar wheel on another axis which carries the eccen- 
trics by which the valves are governed. These eccentrics run loose on 
their shafts; but at a point of the descent of the piston when the piston 
itself is near the bottom of the cylinder, a cam on the rod causes them 



OTTO AND LAN GEN'S GAS-ENGINE. 61 

to be fixed for a single turn, during which the charge of air and gas is 
admitted. 

Figs. 1 and 2 in Plate III represent the parts of this machine which 
are essential to the understanding of its mechanism and mode of opera- 
tion. Fig. 1 is a section through the axis of the cylinder taken parallel 
to the plane of the fly-wheel, and a projection in outline of the other 
parts. A is the cylinder and B the piston represented at the lowest 
point. The piston rod with its rack is distinctly shown. This rack 
gears into Z, the smaller of two spur wheels on the same axis, W, which 
is the axis, also, of the working arbor. The larger of these two spur 
wheels gears into an equal wheel to the left. Since this larger wheel 
is keyed on to the main shaft it turns constantly in the same direction 
as the fly-wheel, and it keeps, of course, the wheel into which it gears 
in uniform motion also. But on the axis of this wheel there are two 
eccentrics, x and y, which, running loose on the arbor, are usually 
motionless. But just as the piston reaches its lowest point, which is 
the position shown in Fig. 1, these eccentrics are seized and carried 
round for a single revolution, in consequence of the dropping of a catch, 
shown at a?, into the ratchet wheel t 1 which is keyed to the arbor. In 
Fig. 2 this catch is shown in its usual position of detent, it being held 
free of the ratchet wheel by a projection on the lever h. When the pis- 
ton reaches its lowest point the end of this lever h is acted on by a 
shoulder in the piston rod, as is seen at w, Fig. 1, and the catch is 
released. Falling into the ratchet t, it is dragged, and with it the 
eccentrics, in the direction of revolution ; but at its first return to the 
position shown in the figure, it is caught again by the projection on the 
lever 7^, (which has now returned to its place,) and brought to rest. The 
manner in which these effects are produced may be thus explained. 
There are two eccentrics on the arbor which are firmly connected 
together, but which are set at about 90° from each other. One of them 
acts on a lever marked m, (seen in both figures.) Its office is to lift the 
piston from the lowest point through the space required for the admis- 
sion of the new charge of gas. That of the second is to act on the slide 
valve shown at s. This slider in the figure is in the position which it 
assumes to admit of the expulsion of the products of combustion after 
each explosion. On the descent of B the valve p opens outward and 
the gases escape. The opening for the admission of the fresh charge is 
not in the same vertical plane as that for the exhaust, and hence it does 
not appear in this section. 

So soon as the piston has reached its lowest point, and, acting on the 
lever li through the shoulder n 1 has released the catch x, one of the 
eccentrics acting upon the lever m immediately raises the piston through 
a space large enough for the aspiration of the new charge. It is, of 
course, necessary that a special provision should be made for this first 
movement of the piston, which is at this moment entirely detached from 
the machine. The lifting of the piston, of course, releases the lever h; 
and this occurs within the first quarter of a revolution, so that the 



62 PARIS UNIVERSAL EXPOSITION. 

eccentrics are necessarily caught when the revolution is complete, while 
at the same time the slide valve is brought into position to cut off fur- 
ther admission of gas, and to introduce a name from a small fixed 
burner for the purpose of firing the charge. 

By the explosion the piston is driven to the top of the cylinder, the 
gear wheel Z running loose on the arbor as it rises ; but on its descent 
immediately after, under the pressure of the atmosphere, this wheel is 
prevented from turning by the catches Jc r, except as it carries the arbor 
with it. As the elasticity of the gases within the cylinder falls almost 
immediately nearly to zero, the effective pressure exerted on the piston 
is almost an atmosphere. 

In Fig. 1, (Plate III,) both the levers li and m are shown at their lowest 
point. In Fig. 2, (Plate III,) h is at its highest point and m at its lowest, 
the piston being now near the top of the cylinder. When, in the revolu- 
tion of the eccentrics, m is also at its highest point, it is higher than the 
position of h as shown in either figure. 

In regard to the performance of this machine, as it respects the quan- 
tity of the combustible consumed and the amount of force developed, 
information was repeatedly sought ; but nothing could be ascertained on 
the subject from the exhibitor, beyond the general statement that the con- 
sumption of gas per horse-power per hour is in round numbers thirty cubic 
feet. Xo details were supplied in regard to the experimental trials by 
which this determination was arrived at. 1 Assuming it to be correct, this 
engine may be said to work economically : though less so than the steam- 
engine. Thirty cubic feet of gas, with gas at twenty-five cents per one 
hundred cubic feet, would amount to seven and a half cents ; while six 
pounds of coal, which in a steam-engine would do the same work, costs 
less than two cents, coal being estimated at 86 per ton. In Paris gas 
costs but seventeen cents per hundred cubic feet, and coal is higher. On 
the other hand it is in favor of the gas-engine that it requires no expense 
of fuel to prepare for work, and that the expenditure ceases at the 
moment the engine is stopped. There is not only in this respect an 
economy of expense, but an economy also of time and of the labor of 

1 The desired information on this point was obtained at a later period from the results of 
experiments made before the jury of class 53, which have beeu published by Professor Karl 
Jenny, of Vienna, a member of the jury. The consumption of gas for the driving' of the 
engine, and that employed for maintaining the burner employed to fire the charges, were 
separately measured. The power developed was determined by means of a Prouy dynamo- 
meter. Four experiments were made, each continuing for half an hour, with the exception 
of the last, which was extended to thirty-four minutes. The power developed varied from 
0.563 to 0.603-horse power ; but in the mean of the four experimeuts was 0.582. The total 
consumption of gas amounted to 1.303 cubic metre, of which 0.105 cubic metre was con- 
sumed by the burner, and the remainder, 1.138 cubic metre, by the engine itself. Consider- 
ing only this last, the consumption per horse-power per hour averaged 0.95 cubic metre, the 
best performance requiring but 0.900 cubic metre, and the worst 1.040 cubic metre. Taking 
into consideration the consumption of the burner, the average total consumption was 1.0S3 
cubic metre. This is twofold the amount required according to the statement of the exhib- 
itor. At the same time it must be remarked that the consumption of the burner, which, 
however, is but a small fraction of the whole, is the same for a large as for a small power. 



OTTO AND LANGEN's AND LENOIR'S GAS-ENGINE. 63 

attendance. And, moreover, the machine is perfectly safe, whether as 
regards liability to explosion or danger of fire. Insurance companies, 
therefore, exact no premium for its installation. On the other hand, it 
must be said of this machine that it does its work by no means silently ; 
and that, unless in a workshop already so noisy that a littiem ore or less 
of din is a "matter of secondary moment, it must be a disagreeable com- 
panion. It need hardly be added, that the violence of its action during 
the first part of each pulsation is such as necessarily to limit its employ- 
ment to low powers. The inventors offer machines at the following 
rates as delivered in Cologne : 

Engine of J-horse power, 350 thalers $130 

Engine of 1-horse power, 450 thalers 170 

Engine of 2-horse power, , . 580 thalers 220 

LENOIR'S GAS-ENGINE. 

The gas-engine of Mr. Lenoir, exposed in the French department, 
employs, like that which has just been described, a mixture of coal gas 
and common air as the source of its motive power ; but it uses the direct 
force developed by the explosion of the mixture to produce motion, pre- 
cisely as the pressure of steam is employed in an ordinary steam-engine. 
This machine was patented in 1860, and is now very extensively in use. 
Paris has one hundred and fifty of these engines in operation, and there 
are at least an equal number at work in the provinces of France and in 
foreign countries. England has seven or eight, and Eussia as many. 
Some few have found their way to Cuba, Peru, and Chili. It is evident, 
therefore, that this machine has achieved a practical success. 

The essential parts of this engine are a horizontal cylinder, with a 
piston which communicates motion by means of a crank to an arbor 
which carries a fly-wheel, and through which the power is to be applied 
to use. The fly-wheel is made very heavy for a double reason. First, 
there is no driving power during one-half of each stroke, and a large 
reserve of accumulated force is necessary to continue the work of the 
engine and to overcome the passive resistances during this period ; and 
secondly, the explosive energy of the gases is great, but is only of very 
brief duration. The inertia of a large wheel is therefore necessary to 
maintain the uniformity of movement necessary to useful work. 

Plate III, Fig. 3, represents the elevation of a machine of one-horse 
power, on a scale one to ten. It will be seen to resemble a steam-engine 
in all its essential parts ; and, as in that engine, it has valves governed 
by an eccentric on the main shaft. The cross-section, Fig. 6, shows 
that the cylinder is surrounded by a jacket. Between this and the 
cylinder itself cold water circulates, to prevent excessive elevation of 
temperature. Figs. 5 and 5a show the construction of the slide-valves, 
and their relation to the cylinder is shown in Fig. 6. The cylindrical ves- 
sels E and E' are the valve-boxes. The gas enters E by the tube e. It 
passes through the orifices d' (Fig. 5) into the cylinder by corresponding 
orifices. Air enters at the same time through the free space between the 



64 PARIS UNIVERSAL EXPOSITION. 

two faces of the slider, (Fig. 5«,) which space, as the same figure shows, 
communicates with the small gas-passage (V. The air and gas therefore 
mingle progressively as they enter the cylinder ; when the piston reaches 
the middle of its course, the slider cuts off further supply, and an electric 
spark from a Euhmkorff coil fires the mixture in the cylinder, and the 
piston is impelled with great force toward the end of the cylinder which 
it is already approaching by the effect of the inertia of the fly-wheel. 

It is easy to imagine many modes in which the rupture of an electric 
circuit may be periodically determined by the motion of a machine. The 
mode employed in this instance is illustrated in Fig. 7. A and B 
represent two elements of a Bun sen battery. A Euhmkorff coil is 
enclosed within the case represented at E. The current from A B is 
carried to / through the interrupter /'. It traverses the principal 
circuit of the coil in E, and then, through the wire li p, passes to the 
inner ring of a circuit breaker, represented in H. This ring is metallic 
and is insulated. Externally to it are the metallic arcs p >•, which are 
also insulated from the inner ring. The two rings are concentric with 
the axis of the main shaft of the engine, and this shaft carries at its 
extremity an insulated metallic arm K, which is always in contact with 
the inner ring, and which makes and breaks contact with the outer arc, 
as the shaft turns. The arcs p and r are connected by wires attached at 
a and b 1 which unite at n with the other pole of the battery. A wire 
from e to m connects the end of the secondary coil with the metal of 
the gas-admission tube T. Another insulated wire d connects the 
other end of the same coil with the binding screws d' and d" , which 
communicate with the interior of the cylinder by two insulated metallic 
points. Fig. 4, K shows the arrangement of these points. Their place 
in the machine is shown in Fig. 3, at K and K'. 

As the principal circuit is broken from time to time at H, a spark 
passes from one or the other of the insulated points, at &' or d", to the 
metal of the cylinder, firing the explosive gases, if there be any present. 
It is of course easy to adjust the circuit breaker H, by turning it on its 
centre, so as to produce the spark at any moment of the revolution 
winch may be desired. 

Xo-air pumps are used with this engine. The inspiration of the gases 
is effected by the movement of the working piston itself. The inflam- 
mable gas is most advantageously taken from a gasometer: but it may 
be taken directly from the tubes supplying the illumination to the build- 
ing, provided there be interposed an elastic bag large enough to hold 
several charges. This contrivance is represented in the last diagram, 
where g is a bag of caoutchouc placed just before the point of admission 
of the gas to the engine. In this bag the gas should be under some 
tension. In the action of the machine, it swells and collapses in a man- 
ner resembling the action of the lungs. 

The proportions in winch the air and gas are mingled is one part of 
gas to thirteen and a half of air. Originally the proportion of gas 



EXPERIMENTAL RESULTS WITH LENOIR ENGINE. 65 

employed was as one to nine, but practice lias shown it to be more advan- 
tageous to employ a greater degree of dilution. 

Instead of the Bunsen batten the simpler sulphate of copper battery 
of Daniell is now generally used. When once arranged, it maintains its 
action for long periods with very little attention. 

The water required for the refrigeration of the cylinder may, in some 
localities, require to be made the subject of a special provision. Where 
there are public water- works supplying an abundance for all purposes, 
there will be no difficulty ; but under other circumstances it is necessary 
that the circulation be maintained by a small pump worked by the 
engine. The water, however, if kept in a large reservoir exposed to the 
weather, will cool fast enough to be used repeatedly, provided the reser- 
voir have a capacity proportioned to the power of the engine, and pro- 
vided also that the supply water be drawn always from the bottom of 
the reservoir, while the escape water is discharged at the top. 

For a half-horse power engine the reservoir should have a capacity of 
500 litres, say 130 gallons ; for one-horse power, 1,200 litres, say 320 
gallons 5 for two-horse power, 2,000 litres, say 530 gallon's ; for three-horse 
power, 3,000 litres, say 800 gallons. 

The Lenoir engine has been made the subject of repeated experiments 
by Mr. Tresca, and from his published results we obtain the most exact 
information in regard to its capabilities that could be desired. In the 
first place, the pressure, which is of course at its maximum immediately 
after the explosion, is shown by the manometer to diminish with singu- 
lar rapidity ; so that if the stroke were not quite short as compared with 
that which is usual with a steam piston of similar diameter, the effect 
would inevitably become negative before its completion. It appears also 
that, with the proportions in the mixture above named, the maximum 
pressure hardly reaches six atmospheres, a pressure not considered excess- 
ive with steam ; but it aifects the indicator with a much more sudden 
start than does steam of the same pressure. 

Mr. Tresca's first observations were made upon a machine of a little 
over one-half of one-horse power. The consumption per horse-power per 
hour was inferred to amount to something more than three cubic metres, 
or over 100 cubic feet of gas per horse-power per hour. With gas at twenty- 
five cents per 100 cubic feet, this would make the power sufficiently expen- 
sive — too much so, in fact — to compete with steam in cases where steam 
could possibly be employed. But as a substitute for the labor of men, in 
turning a windlass, for instance, or in driving a lathe, or a printing press, 
and for many similar kinds of work, it may be practically economical. 
And for intermittent labor, it is a very important consideration that the 
consumption does not go on while the machine is at rest. 

Mr. Tresca subsequently experimented on another of Mr. Lenoir's 
engines, having nearly double the power of the first, or nine-tenths of one- 
horse power. In this case the result was more favorable, the consumption 
being reduced to2.7 cubic metresper horse-power per hour. It is not sur 
5 1 A 



66 



PARIS UNIVERSAL EXPOSITION. 



prising that such a difference should have been found, since small engines 
of all kinds are subject to a more than proportional amount of loss in 
overcoming passive resistances ; and in the present case it may be said 
that the cooling of a small mass of hot gas confined within metal walls 
will be much more rapid than that of a larger body. We may therefore 
reasonably conclude that a Lenoir engine of two-horse power would not 
consume more than two and a half cubic metres per horse-power per hour. 

The prices at which these engines are furnished in Paris are as fol- 
lows : 

Engine of J-horse power, without governor.. .1,100 francs = 8220. 

Engine of 1-horse power, without governor.. .1,600 francs = 8320. 

Engine of 2-horse power, with governor 2,500 francs = 8500. 

Engine of 3-horse power, with governor 3,000 francs = 8600. 



HUGON 7 S GAS-ENGINE. 

The third gas-engine exposed is that of Mr. Hugon. It resembles in 
many respects the engine just described, but presents two or three points 
of difference of some importance. The first concerns the manner of inflam- 
ing the gas. Mr. Hugon, like Mr. Lenoir, first employed the electric 
spark for this purpose ; but, finding that inflammation sometimes failed 
to occur, whether from the failure of the spark or from the imperfect 
mixture of the gases, he abandoned that plan and adopted a more infal- 
lible expedient. This may be understood by referring to Figs. 3, 4, and 
5, which follow : 

These figures represent, in section, the 
cylinder, with the slide-valves designed 
for the distribution and inflammation of 
the gases. All the figures are similarly 
lettered, and represent different succes- 
sive positions of the movable parts. 
These parts are distinguished by the let- 
ters EE and DD. The first is designed 
for the distribution, and the second for 
the inflammation of the gases. The 
gases are admitted from the space F, 
which is the end of a large pipe in which 
they are mingled. In Fig. 3. the slide 
E is in the position which opens com- 
munication with the part of the cylinder 
behind the piston C. The other slide 
D is in a corresponding position, and ir 
will be seen that the passage is free from 
F to the upper part of the cylinder. 
Fig. 3. while between F and the lower part of 

the cylinder communication is doubly cut off. But in this position of 
D the lower part of the cylinder communicates through G- with H. which 
is the eduction pipe for the exhaust gases. 




HUGON'S GAS-ENGINE. 



67 




As the piston advances, the mixed gases continue to flow in from F 
until a sufficient supply has entered the cylinder, when the slide E takes 
the position shown in Fig. 4, and 
communication with the reservoir 
is closed. At the same time the 
slide D advances to the successive 
positions shown in Figs. 4 and 5. 
This slide carries, in two little 
recesses marked B, two gas jets, 
of which the office is to fire the 
charges in the upper and lower 
parts of the cylinder successively. 
In Fig. 5 it will be seen that there 
is an opening by which the upper 
jet B is in communication with the 
explosive mixture above the piston. 
In this manner the mixture is fired. 
But, as the effect of the explosion 
is to exhaust the oxygen in the 
cylinder, the jet B is necessarily 
extinguished. A provision is there- 
fore necessary to insure its being Fig. 4. 
rekindled before its service is again required. In order to accomplish 
this object, a permanent light is placed at A, outside of the cylinder. In 
Fig. 3 the movable jet B 
is represented just oppo- 
site to A, and in this posi- 
tion it is lighted by com- 
munication through the 
free opening on that side. 
In Fig. 4 the lower jet is 
in position to be lighted by 
another permanent light, 
marked A also. 

When the piston reaches 
the end of its course the 
slide D is drawn upward 
so far as to open a free 
communication between F 
and the lower chamber of 
the cylinder. A new charge 
enters on that side; and 



this is fired by the lower 
movable jet B. Thus the 
operation goes on indefi- 
nitely. 




68 PAEIS UNIVERSAL EXPOSITION. 

The space K, which is shown in all these figures, is the interval between 
the cylinder and its jacket, in which cold water is kept constantly circu- 
lating'. This is a provision necessary in every gas engine to prevent 
excessive elevation of temperature. Another expedient which contrib- 
utes to the same end is the introduction into the interior of the cylinder 
itself of a small quantity of water along with every charge of gas. A 
double advantage results from this. By its evaporation the water absorbs 
some heat, and in becoming steam at the same time it prevents the abrupt 
fall of pressure which follows the explosion when the gases are admitted 
entirely dry. The reality of the advantage is made very apparent by 
the curves traced by the index of the manometer, or pressure gauge, 
when the water is present and when it is absent. In the two figures 
which follow, the first, Fig. 6, shows the violent oscillations, and the 
abrupt rise and fall of pressure, which are occasioned by the explosion 
of the gases in the absence of water. The second, Fig. 7, exhibits the 
evidence of the much better sustained pressure produced by the steam. 




In both these figures, it will be seen that the curve descends, on the 
right, for a short distance below the horizontal line. This marks the 
period of admission of the gases to the cylinder when the pressure is 
negative. 

The introduction of water into the cylinder, as here explained, consti- 
tutes the second peculiarity in which the present engine differs from 
that of Mr. Lenoir. The other differences are of minor importance. Mr. 
Hugon's engine employs a kind of bellows worked by the engine for the 
introduction of the gas into the space where it is mixed with air. and he 
effects this mixture before the charge is introduced into the cylinder. 
Mr. Lenoir draws both the gas and the air directly into the cylinder by 
the motion of the working piston itself, and relies for their mingling 
upon the arrangement of the admission tubes. 

In the particulars of its construction this engine differs considerably 
from that last described. Figs. 8 and 9, Plate III. illustrate this con- 
struction. The first is a vertical section through the axis of the cylinder 
and of the working shaft. 



hugon's gas-engine. 69 

The cylinder is shown at A, the small space a being the interval 
between it and the jacket, which is filled with cold water. 
B is the piston with its rod b, guided by the support b'. 

is the connecting rod, which is forked below, and attached above to 
the crank. 

D is the arbor moved by the crank, and carrying the pulley d, by which 
the motive power is applied. The same arbor carries the fly-wheel Y at 
the extremity. 

E is the slide carrying the portable gas jets K K, and serving also to 
open the escape passage to the exhaust gases. 

F is the induction slide, admitting the explosive mixture to the cylinder. 

G is the compressor by which the inflammable gas is introduced into 
the chamber where the mixture is formed. 

1 is the reservoir of inflammable gas. 

J J are the fixed gas jets, and K K the movable. The second figure 
is an elevation of the machine seen laterally. 

Experiments made upon this machine, at the Conservatoire des Arts et 
Metiers, show that its consumption amounts to 2.6 metres cube per horse- 
power per hour. In this is included the amount, which is considerable, 
consumed by the jets employed to inflame the charges. It appears also 
that, as in the case of the Lenoir engine, the maximum pressure is between 
five and six atmospheres, and the mean (effective) pressure throughout 
the stroke less than half an atmosphere. 

The introduction of water into the cylinder of this machine is an 
important feature of its operation, contributing to its efficiency by giving 
greater permanence to the elastic force of the products of the explosion, 
the steam derived from this water being one of these. It would seem 
probable that, by carrying out this idea further than it is here done, 
results might be attained still more favorable. An engine operating 
upon this principle was constructed some years ago, in London, by 
Messrs. W. and C. F. Siemens, and was exhibited at the Exposition of 
1862 5 but it has not been brought forward again in that of 1867. In the 
engine of the Messrs. Siemens the object aimed at was to generate as 
much steam as the heat furnished by the combustion of the inflammable 
gas would allow; and a regenerator was employed to receive the heat of 
the exhaust gases for the purpose of transferring it to the entering charge. 
Though no exact statements of the economy realized in the working of 
the engine of the Messrs. Siemens appear to have been published, it 
would seem, in theory, to be preferable to either of those which have 
here been described, both as it regards the mode of action of the power 
and the cost of maintenance. 

It might be said that an engine which, while nominally a gas-engine, 
owes thus its principal merit to the steam which it generates, is, in fact, 
only a steam-engine in disguise, and might, therefore, better be replaced 
by the steam-engine in its ordinary form. To this it may be replied that 
there is a very essential difference between the present engine and the 



70 PARIS UNIVERSAL EXPOSITION. 

ordinary steam-engine, which consists in the fact that this has no boiler, 
and that it generates the steam which it uses in the cylinder itself. This 
is a very important advantage. The dangers of explosion are removed 
entirely. The machine is always ready for work. The expense ceases 
the moment the work is over; and the work may be interrupted and 
resumed any number of times during the day, without involving any 
waste of fuel during the intervals of repose. To this it may be added 
that gas-engines create no dust or ashes, and require no labor to be 
expended in the transportation of fuel or the removal of cinders. More- 
over their use is attended with no danger of fire to the buildings or the 
apartments in which they operate; and they can, on this account, be 
introduced in localities from which steam-engines would be necessarily 
excluded. And finally, though in -point of economy they may not com- 
pete with steam, yet they may often furnish a convenient power much 
cheaper than the human labor, which they will, in many cases, be employed 
to replace. 

It is one important disadvantage attendant on these engines, that, in 
situations where illuminating gas is not manufactured on the large scale 
for public use, they are unavailable without a special apparatus for gen- 
erating the gas. The engine of Mr. Siemens is accompanied by such an 
apparatus; but the additional trouble which its use occasions cannot but 
be objectionable. It is worthy of consideration whether some of the 
cheap and very volatile hydrocarbons, all of which furnish a vapor which 
is explosible in mixture with common air, might not be advantageously 
employed to replace coal gas. Supposing this to be successfully accom- 
plished, the use of the class of motors under consideration might be very 
largely extended. 

III.— AMMOXIACAL GAS-EXGIXES. 

If hot-air engines and inflammable gas-engines fail as yet to furnish 
power comparable to that which steam affords, without a very dispropor- 
tionate increase of bulk, and for high powers fail to furnish it at all, the 
same objection will not hold in regard to the new motors now beginning 
to make their appearance, in which the motive power is derived from 
ammoniacal gas. This gas, which is an incidental and abundant product 
in certain manufactures, especially that of coal gas. and which makes 
its appearance in the destructive distillation of all animal substances, is 
found in commerce chiefly in the form of the aqueous solution. It is the 
most soluble in water of all known gases, being absorbed, at the tem- 
perature of freezing, to the extent of more than a thousand volumes 
of gas to one of water ; and at the temperature of 50° F. of more 
than eight hundred to one. What is most remarkable in regard to this 
property is, that, at low temperatures, the solution is sensibly instanta- 
neous. This may be strikingly illustrated by transferring a bell-glass 
filled with the gas to a vessel containing water, and managing the transfer 
so that the water may not come into contact with the gas until after the 



AMMONIACAL GAS-ENGINES. 71 

mouth of the bell is fully submerged. The water will enter the bell with 
a violent rush, precisely as into a vacuum, and if the gas be quite free 
from mixture with any other gas insoluble in water, the bell will inevitably 
be broken. The presence of a bubble of air may break the force of the 
shock and save the bell. 

This gas cannot, of course, be collected over water. In the experiment 
just described, the bell is filled by means of a pneumatic trough contain- 
ing mercury. It is transferred by passing beneath it a shallow vessel, 
which takes up not only the bell-glass but also a sufficient quantity of 
mercury to keep the gas imprisoned until the arrangements for the 
experiment are completed. 

The extreme solubility of ammoniacal gas is, therefore, a property of 
which advantage may be taken for creating a vacuum, exactly as the 
same object is accomplished by the condensation of steam. As, on the 
other hand, the pressure which it is capable of exerting at given temper- 
atures is much higher than that which steam affords at the same temper- 
atures 5 and as, conversely, this gas requires a temperature considerably 
lower to produce a given pressure than is required by steam, it seems to 
possess a combination of properties favorable to the production of an 
economical motive power. 

Ammonia, like several other of the gases called permanent, may be 
liquified by cold and pressure. At a temperature of — 38°.5 C, it becomes 
liquid at the pressure of the atmosphere. At the boiling point of water 
it requires more than sixty-one atmospheres of pressure to reduce it to 
liquefaction. The same effect is produced at the freezing point of water 
by a pressure of five atmospheres, at 21° (70° F) by a pressure of 
nine, and at 38° (100° F) by a pressure of fourteen. 

If a refrigerator could be created having a constant temperature of 
0° C, or lower, liquid ammonia would furnish a motive power of great 
energy, without the use of any artificial heat. The heat necessary to its 
evaporation might be supplied by placing the vessel containing it in a 
water-bath, fed, at least during summer, from any natural stream. Such 
a condenser could not be economically maintained. A condenser at 
21° 0, however, and an artificial temperature in the boiler of 38° O, would 
furnish a differential pressure of five atmospheres, with a maximum 
pressure of fourteen. By carrying the heat as high as 50° C, (122° F,) 
a differential pressure of eleven atmospheres could be obtained, with an 
absolute pressure of twenty. 

These pressures are too high to be desirable or safe. Moreover, con- 
densation is more easily effected by solution than by simple refrigera- 
tion, and hence, in the ammoniacal gas engines thus far constructed, the 
motive power has been derived, not from the liquiaed gas, but from the 
aqueous solution. The gas is expelled from the solution by elevation of 
temperature. At 50° C (1*22° F) the pressure of the liberated gas is equal 
to that of the atmosphere. At 80° C (176° F) it amounts to five atmo- 
spheres, and at 100° O (212° F) to seven and a half. At lower tempera- 
tures the gas is re-dissolved, and the pressure correspondingly reduced. 



72 PARIS UNIVERSAL EXPOSITION. 

Iii the ammoniacal engine, therefore, the expulsion and resolution of 
the gas take the place of vaporization and condensation of vapor in the 
steam-engine. The manner of operation of the two descriptions of 
machine is indeed so entirely similar, that hut for the necessity of pro- 
viding against the loss of the ammonia, they might be used interchange- 
ably. The ammonia-engine can always be worked as a steam-engine, 
and the steam-engine can be driven by ammonia, provided the ammonia 
be permitted to escape after use. The advantage of the one over the 
other results from the lower temperature required in the case of ammo- 
nia to produce a given pressure, or from the higher pressure obtainable 
at a given temperature. These circumstances are favorable to the econo- 
mical action of the machine in two ways. In the first place, they consid- 
erably diminish the great waste of heat which always takes place in the 
furnace of every engine driven by heat ; the waste, that is, which occurs 
through the chimney without contributing in any manner to the opera- 
tion of the machine. This waste will be necessarily greater in propor- 
tion as the fire is more strongly urged ; and it will be necessary to urge 
the fire in proportion as the temperature is higher at which the boiler, 
or vessel containing the elastic medium which furnishes the power, has 
to be maintained. In the second place, that great loss of power to which 
the steam-engine is subject, in consequence of the high temperature at 
which the steam is discharged into the air, or into a condenser, is very 
materially diminished in the engine driven by ammoniacal gas. 

For instance, steam formed at the temperature of 150° C (302° F) has 
a pressure of nearly five atmospheres (1.8.) If worked expansively, its 
pressure will fall to one atmosphere, and its temperature to 100° C (212° F) 
after an increase of volume as one to four. If, now, it is discharged into 
a condenser, there is an abrupt fall of temperature of 50°, 60°, or 70°, 
without any corresponding advantage. If it is discharged into the air, 
this heat is just as much thrown away. In point of tact, when steam of 
five atmospheres is discharged into the air at the pressure of one, consid- 
erably more than half the power which it is theoretically capable of 
exerting is lost ; and when, at the same pressure, it is discharged into a 
condenser, more than one-quarter of the power is in like manner thrown 
away. And as the expansion given to steam is usually less than is here 
supposed, the loss habitually suffered is materially greater. 

The ammoniacal solution affords a pressure of five atmospheres at 
80° C, (176° F,) and in dilating to four times its bulk, if it were a per- 
fectly dry gas, its temperature would fall below 0° C. But as some vapor 
of water necessarily accompanies it, this is condensed as the temperature 
falls and its latent heat is liberated. The water formed by condensation 
dissolves also a portion of the gas, and this solution produces additional 
heat. In this manner an extreme depression of temperature is prevented, 
but it is practicable, at the same time, to maintain a lower temperature 
in the condenser than exists in that of the steam-engine. It must be 
observed, however, that owing to the very low boiling-point of the solu- 



ADVANTAGES OF AMMONIACAL GAS-ENGINES. 73 

tion it is not generally practicable to reduce the pressure in the con- 
denser below half an atmosphere. 

The advantages here attributed to ammoniacal gas belong also, more 
or less, to the vapors of many liquids more volatile than water ; as, for 
instance, ether and chloroform. Engines have therefore been constructed 
in which these vapors have been employed to produce motion by being 
used alone, or in combination with steam. The economy of using the 
heat of exhaust steam in vaporizing the more volatile liquid is obvious. 
But all these vapors are highly inflammable, and in mixture with atmo- 
spheric air they are explosive. The dangers attendant on their use are 
therefore very great. Ammonia is neither inflammable nor explosive, 
and if, by the rupture of a tube or other accident, the solution should 
be lost, the engine will still operate with water alone. 

The action of ammonia upon brass is injurious ; but it preserves iron 
from corrosion indefinitely. It contributes, therefore, materially to the 
durability of boilers. A steam-engine may be converted into an ammo- 
nia-engine by replacing with iron or steel the parts constructed of brass, 
and by modifying to some extent the apparatus of condensation. 

feot's ammoniacal gas-engine. 

But one engine was exhibited in the Exposition operated by ammo- 
niacal gas. This was one which had been originally constructed as a 
steam-engine for the imperial marine, and which has been placed at the 
disposal of the inventor, Mr. Frot, of Paris, by order of the Emperor. It 
is of fifteen-horse power. This machine has been made the subject of a 
series of exx)eriments by a commission appointed by the ministry of 
marine, whose report upon its performance has not yet appeared. The 
inventor afiirms, however, that its consumption of fuel per horse-power 
per hour is not more than one-third of that of a steam-engine working 
under similar conditions. The machine being itself a steam-engine, it 
has been possible to make comparative experiments with all desirable 
exactness, by using steam and ammonia alternately. 

The modifications made in the condensing apparatus have been only 
such as are necessary to re-dissolve the gas to a degree of saturation suffi- 
cient to make it available for repeated use, and to return the solution to 
the boiler. For this purpose the condenser has two chambers instead of 
one. In the first the gas, with the steam which accompanies it, passes 
through a series of tubes surrounded by water, where the steam is con- 
densed and the gas is to a certain extent cooled. From this it passes 
into a second, into which is at the same time injected a small quantity 
of water, which, along with the water from the condensed steam, com- 
pletes the solution of the gas. This vessel is called the dissolver, and 
the name condenser is applied only to the one first mentioned. The dis- 
solver is kept cool by means of a series of tubes passing through it, in 
which the water of refrigeration circulates. The water passes first 
through these tubes, and afterwards surrounds the tubes of the con- 



74 PAEIS UNIVERSAL EXPOSITION. 

denser. From the dissolver the saturated solution is withdrawn by a 
pump, which forces it into the boiler. But as the boiler would in this 
way be liable to become overcharged with liquid, while the strength of 
the solution would at the same time grow gradually weaker, care is 
taken to prevent these disadvantageous consequences by drawing from 
the boiler itself the water used for injection. In fact, as the gas is grad- 
ually expelled by heat from the solution in the boiler, and as the specific 
gravity of the solution is greater in proportion as its strength dimin- 
ishes, it will happen that the lower strata will generally be reduced to 
the condition of pure water, or will contain only an insignificant amount 
of ammonia. This portion of the solution is gradually withdrawn in 
measure as the saturated solution is introduced at the top, and after 
passing through a refrigerator is employed for injection into the dis- 
solver. As a further measure of economy, this water, on its way to the 
refrigerator, is made to impart a portion of its heat to the saturated solu- 
tion returning to the boiler, by passing through a jacket siuTOunding the 
tube by which this solution returns. 

With the exception of possible and trivial leakage, the same water and 
the same gas, therefore, keep up a perpetual circulation between the 
boiler and the dissolver, without increase or diminution. In regard to 
leaks every preventive precaution is taken. The pungent nature of the 
gas renders this a matter of no slight importance, apart from considera- 
tions of economy. There is, however, very little leakage, if any at all. 
It could only occur at the surfaces of contact of the movable parts, and 
as these are lubricated with oil, the alkali saponifies the lubricant and 
produces an unctuous compound which, while it answers all the purposes 
of lubrication, closes the joint effectually against the escape of gas. 

Before commencing work it is necessary with this engine, as with the 
steam-engine, to clear all parts of the interior from atmospheric air. 
This is done, as with steam, by blowing through ; but to prevent any loss 
of ammonia in the process, the air which is expelled is passed through 
water, where it leaves in solution any ammoniacal gas which may accom- 
pany it. The same vessel of water being constantly used for this purpose, 
there will gradually be formed a strong solution which may at length be 
employed to feed the boiler. 

It is the statement of the inventor, that any steam-engine may be 
transformed into an ammonia engine at a cost not exceeding thirty dol- 
lars per horse-power. For machines of more than fifty-horse power, the 
proportional expense will be less. The inventor farther states. That the 
cost of making the necessary changes will be largely reimbursed within 
the first year by the saving of combustible. Putting the expense per 
horse-power of the steam-engine for fuel at about a franc a day. or sev- 
enty-three dollars a year, the saving which he proposes to effect, which 
is two-thirds of the whole, will amount to forty-eight il.oUars per horse- 
power, exceeding by more than fifty per cent, the cost oi tlic transforma- 
tion of the engine. 



75 

Mr. Frot is not the only inventor who has occupied himself with this 
application of ammonia. In 1859 a patent was taken out in Paris, by an 
inventor named Delaporte, for an engine working upon the same prin- 
ciple as that which has just been described. 

delaporte's ammonia-engine. 

Other patents have been taken out for similar machines in America, 
and perhaps in England, but it is not known how far they have been 
brought into use, if, indeed, they have been so as yet at all. Fig. 8 repre- 
sents one of these machines, all of which necessarily resemble each 
other in substance, though they may differ in details. 

Fig. 8. 




Delaporte's Ammonia-engine. 

A is the boiler, D the cylinder, and B the tube communicating between 
the cylinder and the boiler. C is the valve box and x the slider by means 
of which the gas is introduced alternately above and below the piston. 
E is the eduction pipe and F the condenser and dissolver. In this 
machine, the condenser and dissolver are not separate, as in Mr. Frot's. 
The water of injection is introduced by a pipe and rose jet at the top of 
the condenser F. The solution passes from F into H, from which it is 
withdrawn by the piston H, passing through the reservoir Jc and the tubes 
U and V by which it is returned to the boiler. As its return is opposed by 
the elasticity of the gas in the boiler, it must be forced in, and a small 
forcing pump, is employed for this purpose. The tube V is surrounded 



76 PARIS UNIVERSAL EXPOSITION. 

by a jacket L. The water which has been deprived by heat of its 
ammonia is withdrawn from the bottom of the boiler by the lower tube, 
and passes into the jacket L, where it imparts a portion of its heat to the 
solution in the tube V, which is on its way to the boiler. It is then 
discharged at I by a connection, not sIioavu, and carried through a refrig- 
erator, which is also not shown, after which it is conveyed into the vessel 
T, and is employed for injection into the dissolver F. 

There seems to be little reason to doubt that the ammoniacal engine 
is, in fact, more economical in its operation than most forms of the steam- 
engine. But the principal theoretic ground on which inventors have 
usually endeavored to prove that it ought to be so is one which is by 
no means tenable. This ground is, that the latent heat taken up by 
ammonia when expelled from its aqueous solution is less than that of 
steam. As what we have denominated the economical coefficient of an 
engine driven by heat is entirely independent of any question concern- 
ing the latent heat of the elastic medium employed, such reasoning is 
altogether fallacious. But as this species of argument is continually 
presenting itself anew, not merely in the case of ammonia but in that 
of a variety of other gaseous or volatile substances, it may not be inap- 
propriate to devote a few words to an examination of the fallacy. In 
point of fact theory is too frequently appealed to in the discussion of 
economical questions connected with this subject, by persons whose 
reasonings show them to be unacquainted with the fundamental truths 
of thermo-dynaniics, aud unaware that they are contradicting established 
principles of the science to which they appeal. Between two given 
machines driven by heat, and performing each the same amount of work 
in the same time, the question which, if either, is the more economical, 
is really more a practical than a theoretic question, and one which 
must be settled experimentally. Theory can only indicate a certain 
limit beyond which economy cannot be carried, and point out the con- 
ditions which favor the attainment of this limit. These are, large expan- 
sion, the suppression of losses by radiation, conduction, leakage. £c 
and the employment of regenerators. But between two machines in 
which these conditions are equally observed, and in Avhieh the maximum 
and minimum temperatures are the same, theory furnishes no ground 
for supposing that there will be any economical difference. The ques- 
tion is not in the least affected by the substitution of one elastic medium 
for another, heated air, the vapor of ether or chloroform, or ammoniacal 
gas, for instance, instead of steam : while the limits of temperature are 
the same, the proportion of heat converted into work, and the propor- 
tion merely transferred from the furnace to the condenser without con- 
tributing anything to the work performed, will be the same for all. It 
is true that with the same difference between the upper and lower tem- 
peratures, there will be a theoretic advantage in favor of the machine 
in which the absolute temperatures are lowest, but practically the lower 
limit of temperature cannot be depressed below the temperature of the 



RELATIVE ECONOMY OF DIFFERENT ELASTIC MEDIA. 77 

natural waters which furnish the means of refrigeration; and this lower 
limit is equally available for all machines. 

It cannot, in fact, be too much insisted on, that the largest prospect 
of improvement in regard to the economy of engines driven by heat is 
in the direction of the better application of the heat of the furnace. The 
principal loss is in that large amount of heat which merely passes 
through the flues of the chimney, without being absorbed by the elastic 
medium at all, and which is, of course, mere waste. 

Many inventors of engines which employ substitutes for steam, and 
among them the inventor of the ammoniacal engine in the Exposition, 
insist very much on the difference between the latent heats of different 
vapors, as affecting the economy of the use of those media as sources of 
power. Latent heat is treated by them as a dead weight to be carried, as a 
simple charge upon the machine, to the efficiency of which it contributes 
in no manner whatever. And yet nothing can be more true, or more 
easily demonstrated, than that the proportion of heat converted into 
work by a machine working between two given limits of temperature, 
under the conditions required to secure the largest theoretic economy, is 
always precisely the same invariable fraction of the total heat received 
from the source, no matter whether this heat be received in the form of 
latent or of sensible heat, and no matter what may be the nature of the 
elastic medium employed to operate the machine. 

It has been shown, in fact, earlier in this report, that in a machine 
driven by heat which fulfils the conditions of the highest economy, there 
are four stages through which the elastic medium successively passes 
in performing one elementary portion of the work and coming back 
again to its original condition. These are, first, expansion at the supe- 
rior temperature maintained uniform by constant addition of heat ; 
secondly, expansion with depression of temperature, no heat being added 
or taken away; thirdly, compression at the inferior temperature main- 
tained uniform by constant withdrawal of heat ; and fourth, compression 
with elevation of temperature without addition or subtraction of heat, 
and with a final restoration of the original condition. 

If we suppose the heat to be derived from an indefinite source at the 
superior temperature, denoted by A, and discharged, in so far as it is 
not converted into work, into an indefinite receiver maintaining con- 
stantly the inferior temperature and denoted by B, then any engine 
whatever, which, working under the conditions of highest economy, per- 
forms between these limits an amount of work, W, must receive from A 
the same amount of heat, H, and impart to B the same amount H 7 , no 
matter what be the nature of the elastic medium through which the 
work is done. 

For if this be not true, then there is a possibility that, of two machines 
which we will call C and D, both performing the same amount of work 
W between the limits, A and B, of temperature, and working under 
conditions of the highest economy, one may take more heat from A, and 
transfer of course more heat to B than the other. Let 0, for instance, 



78 PARIS UNIVERSAL EXPOSITION. 

take from A the amount of heat X, and transfer to B the amount X'. 
Let D in like manner take from A the amount Y, and yield to B the 
amount Y', and suppose X to be greater than Y. X' is less than X by 
the amount of work done ; and Y' is less than Y by the same amount. 
That is, X — X' = W = Y — Y'; and X — Y = X'— Y'. 

Xow as the machine C or D, receiving heat from A and transferring 
it to B, performs the work, TT, it is only necessary to reverse the action 
of this machine, or to drive it backward, by force, in order to restore to 
A the heat taken from it ; which in this case will be partly taken from 
B, and partly supplied by the conversion into heat of the force required 
to drive the machine backward. This force will of course be that repre- 
sented by the work AY. For simplicity, let it be supposed X=2Y. 
Then if the machine be driven backward, it will transfer to A an 
amount of heat equal to 2Y at every revolution : and to do this it will 
consume an amount of work equal to AY. But the machine D, worked 
forwards, will furnish this same amount of work TT, while taking from 
A only the amount of heat represented by Y. The machine C worked 
backward will therefore supply heat enough to work two machines like 
D, or one machine like D of double power. This machine of double 
power may then itself be employed to drive the machine C backward ; 
and in this case it will keep up the supply of heat necessary to sustain 
its own movement, and will have the amount of work, TV, constantly to 
spare. In other words, we shall have an efficient engine without any 
expenditure of any kind to maintain it ; that is to say. a perpetual motion. 

Differences of latent heat and differences of specific heat have there- 
fore nothing to do with the question of relative economy, in the employ- 
ment of different elastic media as substitutes for steam. It is accord- 
ingly unnecessary to examine the correctness of the statement of the 
inventor of the engine under consideration, on which he strongly insists 
as one of the reasons why it must be economical, viz., that the latent 
heat of ammonia in solution is only 126° C, contrasting this with the 
latent heat of steam which he states at 606°.o C. 1 If it were true that 
latent heat is a mere dead weight, contributing nothing to work, then it 
would be equally true that the economical difference between two media 
would amount to the entire difference between the latent heats of the 
two 5 and in the case here presented, supposing the numbers correct, 
it would be enormously more in favor of ammonia than the inventor 
pretends to claim. 

On the other hand, if it is true that the largest possible proportion oi 
the heat which can be converted into work in the use of any medium 
whatever is expressed, as we have seen that it is. by the same invaria- 
ble coefficient ; and if this coefficient is a simple function of the extremes 

1 This is the latent heat of water supposing it evaporated at zero. As the evaporation in 
the steam-boiler takes place in fact at 100° C, or above, the latent heat will not exceed 
537° C, to which, in computing expenditure of heat may be added the difference between 
100° C and the temperature of the feed water. If the boiler is fed with the water from 
the condenser, 30° or 35 c added to the latent heat may give the expenditure. 



RELATIVE ECONOMY OF DIFFERENT ELASTIC MEDIA. 79 

of temperature between which the work is done, then it follows that a 
great latent heat is an advantage, and not a disadvantage, in practical 
thermo-dynamics. For the coefficient gives the value of the heat which 
is converted into work in the form of a determinate fractional part of 
the whole heat received by the medium ; and the greater this whole heat 
is the greater, of course, must be the fractional part. The formula is — 

W being the work, H the whole heat received, T the superior and T' 
the inferior temperature reckoned from the absolute zero. 

This H depends on two things : first, the capacity of the medium for 
heat while in the liquid state below the point of vaporization 5 and, 
secondly, the latent heat of the vapor. Let us suppose that we have a 
condenser which can be maintained at the low temperature of 60° F. 
This supposition is made not as ordinarily practicable, but as a possi- 
bility, in order to found a calculation upon a pretty large range of 
temperature. Let us now consider the amount of work which could be 
done by one pound of water evaporated at 212° F and condensed at 
60° F, and compare it with the amount of work which a pound of ether 
would do between the same temperatures. We have for water, specific 
heat and density, unity ; boiling point, 212° • and latent heat of vapor, 
966 units. 

Between 60° and 212° a pound of water absorbs 152 units. 

And in vaporization at 212° 966 units. 

Total heat absorbed, or value of H= 1, 118 units. 

Hence, W=l,118 i^=251.7 units=195,224 foot-pounds, or nearly 

100 tons raised one foot. 

In the case of ether, we have — 

Specific heat of liquid 0. 517 

Specific heat of vapor 0. 481 

Boiling point under atmospheric pressure 95° F. 

Latent heat of vaporization 162. 8 units. 

Density of liquid 0. 716 

From these data we find the total heat absorbed between 60° and 
212o, thus: 

Between 60° and 95°, 35° x 0.517. . . 18. 095 units. 

In vaporization 162. 8 units. 

Between 95° and 212° ■. 56. 277 units. 

Total absorbed, or value of H for ether 239. 172 units. 

And W=239.172^|°=54.1 units=41,415 foot-pounds, or hardly 21 
tons raised one foot. 



80 PARIS UNIVERSAL EXPOSITION 

This result appears paradoxical, when it is stated that the pressure of 
ether vapor at 212° exceeds six and a half atmospheres, and that it con- 
tinues to be nearly half an atmosphere even at the low temperature 
assumed for the condenser, (60°,) while steam at 212° has only an elastic 
force equal to one atmosphere, and at 60° is reduced to the sixtieth part 
of an atmosphere. The difficulty disappears when it is considered that 
it is not pressure only, hut volume, and change of volume during change 
of temperature, which determines the work which can be done by heat 
operating through a given weight of any medium. At 212° a pound of 
ether vapor occupies but about one cubic foot, (0.9952 cubic foot,) while 
at the same temperature a pound of steam fills a bulk of 26.36 cubic feet. 
At 60° the ethereal vapor will be dilated to a bulk of only 10^ cubic feet, 
while the steam will have expanded to 1,200 cubic feet. Suppose one 
pound of each of these vapors to occupy a cylindrical space which it is 
capable of filling to a depth of one foot, the cross-section in the case of 
steam would be 26.36 square feet, and in the case of ether vapor 0.9952 
square foot. If, then, these vapors are further supposed to be confined 
in these cylindrical cavities by movable pistons, the absolute pressure 
exerted by them severaUy upon these pistons will be — 

For steam, 26.36 sq. ft.xl atm.=26.36x 2116.8 lbs. =55798.818 lbs. 
For ether =0.9952 sq. ft. x 6.5 atm.=0.9952 x G.o X 2116.8=13693.156 lbs. 

Thus, the absolute pressure which measures the possibility of doing 
work is four times as great in the case of the pound of steam as in that 
of the pound of ether. And in expanding between the limits, 212° and 
60°, the pound of steam enlarges its bidk forty-six times, while the expan- 
sion of the ether is not equal to eleven. On both these accounts water 
will have the advantage of ether as a liquid to be used in elastic vapor 
engines. 

But as in practice expansion is carried only to a limited extent, it may 
be more satisfactory if we test the effects of the two vapors on the supposi- 
tion that each increases its bulk by expansion to the same proportional 
extent, as, for instance, in the ratio of one to two. Ether vaporized at 
the temperature of 212°, and expanded with falling temperature to 
double its bulk, will have a resulting pressure of very nearly three 
atmospheres. If we suppose the work done in the meantime to be 
equivalent to that which the mean of the initial and final pressures, con- 
tinued constant from the beginning to the end of the movement, would 
be capable of doing, the work of expansion will be — 

0.9952 x 1.75 x 2116.8=10. 006 foot-pounds, nearly. 
To which add work of enlargement by vapori- 
zation 13. 693 foot-pounds, nearly. 



Total work, ether vapor at 212° to 

twice its volume 23. 099 foot-pounds, nearly. 



In the case of steam, expansion to twice the volume will reduce the 
pressure to 990 pounds per square foot ; and if we take, its before, the 



RELATIVE ECONOMY OF DIFFERENT ELASTIC MEDIA. 81 

mean of the initial and final pressures, it will give ns an equivalent 
constant pressure of 1,553 pounds. The work done by the pound of 
steam during expansion will then be — 

2G.36 x 1,553=40, 037 foot-pounds, nearly. 
And that done during vaporization =55, 700 foot-pounds, nearly. 

Total work, steam at 212° to twice its 

volume 06, 736 foot-pounds, nearly. 



Where the same ratio nearly is manifest as before, steam performing 
more than four times the work of ether vapor. 

It may be observed that the work actually done during expansion is 
not so great as the computation, founded on the assumption of a constant 
pressure equal to the arithmetical mean between the initial and final 
pressures, makes it ; but the error of the result falls in the same direc- 
tion in both cases, and, for the purpose at present in view, is not impor- 
tant in either. 

The conclusion we arrive at is, that steam, as a vehicle for heat in 
machines, is preferable to ether vapor, and generally to the vapor of any 
liquid which absorbs in evaporation a less amount of latent heat than 
steam, so far as the physical properties and relations of the vapors 
themselves are concerned. And it is obvious in this comparison that, 
other considerations apart, the smaller weight and still smaller bulk of 
the liquid which it is necessary to use in order to secure a determinate 
amount of work when water is employed, will always be a sensible 
advantage on the side of steam. On the other hand, the waste of heat 
in furnaces, against which remedies are always more difficult of applica- 
tion in proportion as temperatures are higher, will probably be less with 
the more volatile liquids than with water, so that an ammonia engine 
may very possibly, or even probably, be an economical and a useful one ; 
but this will not be because the latent heat of the gas, as liberated from 
the solution, is less than that due to its evaporation from the liquefied 
state — say 000 units — but because it is not so. 

The ammonia engine, employing the aqua ammonia of commerce, 
works between the extreme temperatures of 230° F and, say, 100° F, and 
is capable of utilizing a fraction of the heat received, represented by the 
difference of these temperatures =130° divided by 460° +230° =600°, 
being the temperature at the upper limit reckoned from the absolute 
zero. This fraction is 0.188, or nearly nineteen per cent. 

A steam-engine working between 300° F and 120° F (in the condenser) 

would, theoretically, be able to utilize |^o^4oo=^= - 2474 ^ or 

nearly a quarter of the heat. But if discharged after dilating to four 
times its original bulk it will produce only half the useful effect above 
computed; that is to say, something over twelve and nearly twelve and 
a half per cent. 
Neither the one nor the other of these engines will probably produce, 
6i A 



82 PARIS UNIVERSAL EXPOSITION. 

in actual practice, the amount of useful effect here credited to them. 
The steam-engine may give ten per cent, and the ammonia engine twelve. 
But it is not here that we shall find the source of the practical economy 
realized, if it has been realized, in the substitution of ammonia for steam. 
This economy probably results mainly from the practicability of main- 
taining the pressure in the boiler with a less intense furnace heat ; and 
the gain is not in the diminished heat required to produce a given work, 
but in the diminished waste in that portion of the heat which does not 
enter the boiler or contribute to the work at all. 

IY._EOTAEY STEAM-ENGINES. 

No effort has more persistently occupied the ingenuity of inventors 
than the attempt to produce rotary motion by the direct action of steam. 
The varieties of rotary engine already produced are almost infinite in 
number, and every year brings new competitors of the same class for the 
approbation of the industrial world. 

The only advantages, however, which can be claimed for a rotary over 
a reciprocating engine are a greater compactness of form and a possibly 
superior simplicity of construction. If in this last particular any pro- 
posed rotary fails, it may be safely assumed that it will never come into 
general favor. Compactness of form is desirable in the engines employed 
for iJirrposes of locomotion, whether upon land or water : but in most 
other situations compactness is an advantage of secondary importance. 
It is to be noted, however, that, as yet, no rotary engine has been con- 
structed possessing anything approaching to the power necessary for 
ocean or even for river navigation ; and hence that invention in this 
direction has, as yet, accomplished nothing of what is most desirable, 
and what may be said to be really needed. 

The principal reason of the imperfect success which has attended this 
description of effort is probably to be found in the great difficulty of 
securing a satisfactory packing of the piston without excessive friction, 
or one which should continue to perform well permanently. A similar 
difficulty exists in regard to the fixed (or occasionally movable) fulcrum, 
against which the steam must react in order to move the piston. On this 
account there is scarcely a single rotary engine in existence in which 
there is not great loss of effective pressure in consequence of the pres- 
ence of steam behind the piston, and not one which could bear enlarge- 
ment to the dimensions required to propel an ocean steamer without 
such loss on this account as to make it economically unavailable. 

THE BEHRENS ROTARY ENGINE. 

The Exposition has presented several forms of rotary engine which 
seem to be superior to most of their class. Of these the most remarkable 
is an American invention, patented in this country in 1866, and subse- 
quently in Great Britain, France, and Belgium. The construction ox 
this engine can hardly be explained without reference to figures. Its 



ROTARY STEAM-ENGINES. 



83 



general external appearance is represented in the perspective view 
annexed, Fig. 9, and its interior is shown in section in the several fig- 
ures, 10, 11, 12, and 13. 




Behren's Rotary Engine. 

It will he seen that there are in the same solid casting two cylindrical 
cavities which overlap each other. In the centre of each cylinder is a 
solid cylindrical core. Between each of these cores and the surface of 
the corresponding cylinder is a piston of peculiar shape, being part of a 
solid ring, filling up the intermediate space as far as it goes, and fitting 
both to the cylinder internally and to the core. These pistons are firmly 
attached to axes, which appear in section at and C in the figures. 



84 



PARIS UNIVERSAL EXPOSITION. 




Fisr. U. 



The maimer of attachment is shown in the perspective view of one of 
Fig. io. the pistons with its axis in Fig. 10. 

The axes are connected externally 
to the cylinders by equal gear- 
wheels, so that they move simul- 
taneously and with equal veloci- 
ties. The two centres of motion, 
and C, are distant from each 
other about two-thirds of the com- 
mon diameter of the cylinders ; and the cores c and c', which in their 
entire dimensions would he too large to allow the pistons to revolve, are 
reduced on the inner sides to a proper curvature to fit the piston exactly 
as it passes. Steam is introduced through the tube B and discharged 
through D. In Fig. 11 it will be seen that the pressure will be on the 
concave face of E', produc- 
ing motion in that piston, 
while it will be directed to 
the centre of motion of E, 
which will therefore form 
the resisting fulcrum. The 
opposite state of things is 
shown in Fig. 12, in which 
E receives the propelling 
force, and E 7 presents the 
resistance. 

The simplicity of construc- 
tion of this engine highly 
recommends it. Its large 
surfaces of contact, cylindri- 
cal in form, and therefore 

Fig-. 12. easily adapted to each other, 

render it little liable to loss 
of power by leakage, and 
make special artifices of pack- 
ing unnecessary. It is obvi- 
ously as well adapted to water 
or heated air as a motive 
power as to steam. If re. 
versed in direction and driven 
by another motor it forms a 
most efficient pump. It can 
be used with steam expan- 
sively. It has iio dead point, 
but will start equally well in 
any position. 

On the other hand, it may 





ROTARY STEAM-ENGINES. 



85 



Fig. 13. 



be observed that it requires a larger amount of steam per revolution to 
drive it than engines of its class generally having the same cross-sec- 
tion of piston and the same diameter of cylinder. It will be seen, 
indeed, that, in order to bring the piston E from its position in Fig. 10 
to its position in Fig. 11 — that is to say, in order to effect a half revolu- 
tion — the entire space marked a must be filled with steam, and also 
the cavity M ST between the piston and the core. But if a line be 
drawn joining p s it will be a diameter of the cylinder. Hence, it is 
evident that considerably more than half the ring in which the piston 
moves has to be filled with steam every half revolution. 

By assuming a position of 
the two pistons such as it is 
just as E is about to cease 
being the propeller and E' 
is on the point of becoming 
such, which is represented 
in Fig. 13, the amount of 
space which has to be use- 
lessly filled with steam may 
be shown distinctly enclosed 
by itself, as it occupies the 
closed cavity MNr«. It is 
not difficult to find the pro- 
portion which the capacity 
of this space bears to the 
total supply of steam during 
the half revolution. The curved face of the piston is practically cylin- 
drical, and its radius may be taken to be equal, as it is nearly, to 
that of the core. Then taking the dimensions of the machine exposed, 
in which the interior diameter of the cylinder is sixteen inches and 
that of the core eight inches, the distance of the centres of rotation 
being eleven inches, we shall find by computation that fully fifteen per 
cent, of the steam admitted is productive of no effect. This is a disadvan- 
tage, but the other merits of the engine are such that it is probably 
destined to come into extensive use. 

PILLNER & HILL'S ROTARY ENGINE. 

Another rotary engine was exhibited by Messrs. Pillner & Hill, of 
Newport, England, which in external appearance presents some resem- 
blance to the one just described. Like that it has two cylindrical cham- 
bers in the same casting, and two systems of rotary pistons. The 
rotating parts, however, which are shown in Fig. 14, herewith given, 
essentially differ from those of the Behrens engine, being in the form of 
two deeply indented gear wheels working into each other. These wheels 
by the close contact of their cogs prevent the passage of steam between 
them, and they are adapted steam-tight to the interior of their cylinders 




86 



PARIS UNIVERSAL EXPOSITION. 



by metallic packing in the tips of their teeth. Practically it is found to be 
sufficient to pack two teeth diametrically opposite to each other in each 



Fig;. 14. 




Pillner & Hill's Rotary Engine. 

wheel. It is of course necessary that the wheels, at their plane extrem- 
ities, should be in close contact with the interior walls of the cylinder : 
and in order to effect this, one of the cylinder heads is made adjustable, 
and may from time to time, if the moving parts by friction should work 
Fig. 15. loose, be brought up by a screw acting upon a wedge- 

jTj^T] shaped plate, as shown in Fig.15. Another mode of 

7 " ! accomplishing the same object is by affixing plates to 
M the lateral surfaces of the wheels, which plates are 
fv pressed outward by springs — that is to say. by a kind 
^ of metallic packing. 

The manner in which the steam acts to produce motion 
in this machine will be understood from an inspection of 
the figure. The induction pipe is at cl, and the discharge 
takes place at e. The steam enters the cylinder imme- 
diately under the centre of the system and presses on 
the teeth of both wheels in opposite directions. At the 
point where the teeth are interlocked, however, the 
surface pressed is practically equal to but a single tooth. 
|H while the contrary pressures are exerted upon two. The 
wheels therefore rotate in the direction of the arrows 
with a force equivalent to the balance of pressure — 
that is, to the total pressure on a single tooth. 

The efficacy of this engine depends very much upon 
the accuracy with which the teeth of the gear wheels lit each other, and 




ROTARY STEAM-ENGINES. 87 

upon the preservation of this close contact throughout the movement. 
It is affirmed that this object is completely secured, and that the effect 
of wear is to improve rather than to injure the performance of the 
machine. It is further affirmed that steam may be used in this engine 
expansively. 

In the model exhibited, the diameter of the cylinders is 20 inches, the 
depth of the teeth nearly four inches, and the length 36 inches. The 
aggregate calculated horse-power, under a pressure of 40 pounds to the 
square inch and with 200 revolutions per minute, is nearly 140. This 
very greatly exceeds the power of any rotary engine heretofore con- 
structed. 

It hardly need be said that this engine is capable of being used as a 
water engine, or as a pump for liquids. And here the remark may prop- 
erly be added that, although the invention is claimed as original by Messrs. 
Pillner and Hill, it was patented in this country thirty or forty years 
ago by Asahel Hubbard, of Vermont, as a water pump, and was manu- 
factured on a large scale for that purpose at the works of the American 
Hydraulic Company, at Windsor. The principle was also embodied in a 
rotary fire engine, manufactured by the same company, which enjoyed 
an extensive popularity. Many of these engines, constructed in the com- 
pany's works at Windsor, were sold and used in the principal cities of 
the United States earlier than the year 1836. The pump is yet in use in 
many parts of the country for domestic purposes, and it is believed that 
the manufacture is still continued. 1 

Messrs. Pillner and Hill have improved the packing of the machine, 
but in principle they have made no change whatever. 

THOMPSON'S ROTARY ENGINE. 

A third form of rotary engine, exhibited by Mr. E. W. Thompson, of 
Edinburgh, appeared to embody in its construction a greater degree of 
ingenuity and originality than has been shown in any invention of its 
class heretofore produced. It is called by the inventor a differential 
engine, for a reason which will appear when its operation is under- 
stood. This engine is represented in the figures which follow. Fig. 16 
is a section through the cylinder at right angles to the axis. It will 
be seen by comparing these figures that there are two pairs of pis- 
tons, each pair being attached to a core which occupies but half the 

1 General Morin, in a passage in his treatise, " Des Machines et Appareils destines a l'ele- 
vation des Eaux," encountered since the statement in the text was written, describes this iden- 
tical pump, and furnishes a figure of it, which essentially resembles the engine of Messrs. Pill- 
ner and Hill, and concludes with the remark: "This arrangement, early known, has been 
produced in our days as new. (See the collection of Grollier de Serviere, Lyons, 1719.") 
The correspondent of the London "Engineering," at the Exposition, also remarks of it, 
"There is nothing new in this contrivance which is a reproduction of Murdoch's rotatory 
engine of the last century, and it in its turn is a copy of the Machina Pupperheimana, fig- 
ured as a pump in Leupold's Theatrum Machinarum, published in 1727." Thus it appears 
that neither the American nor the British invention can claim the merit of originality. 



88 



PAEIS UNIVERSAL EXPOSITION. 



length of the cylinder in the direction of the axis. Each pair of 
pistons is thus attached to its own cone only for half the piston 
length, while the other half projects over the core belonging to the 
other pair. Neither pair of pistons can therefore pass the other. 



Fig-. 16. 




^ 



0.30™ 



though they may come into contact. Each pair of pistons has its 
independent shaft, and externally to the cylinder each of these shafts 
carries an elliptical gear-wheel, which works into an equal and similar 
wheel upon a shaft parallel to the piston shaft. This second shaft, which 



Fig". 17. 




Fist. IS. 




is the working shaft, is provided witn a fly-wheel regulator. The rel- 
ative position of the shafts and the connection of the gearing is shown in 
Fig. 19. The working shaft carries, of course, two elliptical gear-wheels : 



Thompson's rotary steam-engine. 89 

and these are set with their major axes at right angles to each other. 
The elliptical wheels upon the piston shafts have their longer axes at 
right angles to the pistons. Supposing then the engine to be in that 
point of the revolution which is illustrated in Fig. 16, the nearer pair of 
its pistons will be vertical and the more distant pair horizontal. If we 
disturb it from this position, by turning the fly-wheel by hand, it will be 
evident that the remoter piston will be forced to revolve faster than the 
nearer one, because the gear-wheel on the working-shaft acts in the for- 
mer case by its longest radius, and in the latter by its shortest, while the 
opposite is true of the wheels on the piston shaft. The pistons will 
therefore approach each other on one side and become more widely sep- 
arated on the other, assuming ultimately the j)osition shown in Fig. 17. 
It is evident, however, that the velocity of rotation of the remoter piston 
will be regularly retarded and that of the nearer accelerated, so that 
after a time it will be the nearer which will move fastest and the more 
distant which will move slowest. From the position shown in Fig. 
17, therefore, the pistons will at first separate, and afterward come 
together again by their opposite faces. 

Now if we suppose the pistons to be moved from the position shown 
in Fig. 18 to that shown in Fig. 17, we shall see that the spaces 1/ and L 2 
will be enlarged and will draw in air through O and O', while afc the 
same time the spaces L 3 and L 4 will be reduced in capacity so that the 
air will be expelled from them. Or if water should be supplied through 
O and O', the machine might be used as an aspiring or forcing pump, 
the power operating it being applied through the shaft which carries 
the fly-wheel. If, however, instead of sucking in the air or water through 
O and O 7 , we force it in with a pressure superior to that of the atmosphere, 
motion will take place in the opposite direction, and the machine will 
become a motor. Each piston, with its shaft and gear-wheel, may indeed 
be regarded, at any given moment, as a lever, exerting an effort to turn 
the working-shaft ; but each exerts its effort in an opposite direction to 
the other. The power applied is the same in both cases, since it is the 
pressure of the steam on the equal surfaces of the pistons ; the arm of 
the lever on the side of the power is also the same for both. The effect, 
however, is generally unequal, because the arm on the side of the resist- 
ance is usually greater for one than for the other, and, moreover, the 
distance of the point of application of the force from the axis of the work- 
ing-shaft is also variable. This shaft will, therefore, turn with a force 
equal to the difference of the opposing forces ; and this is the feature 
from which the engine takes its name. 

The extent of the relative movement of the pistons will depend, of 
course, upon the degree of ellipticity of the gear-wheels. On supposition 
that those wheels were circular, there would be no relative change of posi- 
tion at all. 

When the ellipticity to be used has been determined upon, it is easy to 
calculate, or to find experimentally, what will be the limit of nearest 



90 



PARIS UNIVERSAL EXPOSITION. 



approach of the pistons. This having been ascertained, it is important 
that the pistons themselves should receive snch form and dimensions as 
to cause them, at the moment of nearest approach, to come into absolute 
contact, in order that there may be no dead or useless space for the 
waste of steam. It is this consideration which has caused the piston 
in this engine to be constructed as shown in the figures, in the form of 
sectors. But as the ways for the entrance and discharge of steam have 
to be placed at a certain distance from each other, for a reason which 
will presently appear, it is necessary that the piston should not be in 
full contact with the cylinder except in the middle point of its bulk, 
where contact is secured, as shown in the figures, by a metallic packing. 
The point of nearest approach will be that at which the velocities of 
the two pistons become equal; for as they approach while the following 
piston moves fastest, they must begin to separate so soon as the leading 
piston begins to gain. It may be said to be self-evident, and at any rate 
it is easily proved, that when the velocities become equal, the radii 
which are for the moment engaged in the gear-wheels on the side of the 
working shaft must be equal to each other; and also that those engaged 
at the same time on the side of the piston shafts must be equal to each 
other. The first of these conditions requires that the major axes of the 
ellipses on the working shaft should be at that moment inclined 45° to 
the line connecting the centres of motion of the parallel shafts. The 

Fis:. 19, 




End view of Thompson's Rotary Engine. 

angle simultaneously made by the major axes of the ellipses on the piston 
shaft, will be the limit of nearest approach of the pistons. 



91 

If we suppose the engine to be in the position represented in Fig. 19, 
and call the piston- wheel which is presented horizontally, A; the wheel 
into which it works, B ; the remoter wheel on the same shaft, C ; and 
the remoter piston-wheel, D; then, according* to what has just been stated, 
B and must advance 45° to bring the pistons to the position of nearest 
approach. The proof of this is as follows: 

The relative angular velocity of wheels gearing into each other is 
inversely as their radii drawn to the point of contact. If these radii 
are represented for the several wheels, in the order in which they have 
been named above, by the letters R x R 2 R3 R47 and if the angular velocity 
of A at any moment be represented by ^, that of B or of C, which is the 
same, by «, and that of D by <w, then we shall have 

(p : s : : B 2 : Ri 5 and s : oj : : R 4 : R 3 . 

Whence « = ^ <p =^ 4 « and a, = ^-^V 
R 2 R3 R 2 R4 

And since v and a> must be equal at the moment of nearest approach, 

we have at that moment 

R!R3 = R 2 R 4 . 

Now if the major and minor axes of the wheels be represented by a 

and &, it is evident from an inspection of the figure that the distance 

between the centres of motion of either of the pairs of wheels which 

gear into each other, must always be equal to a -f Z>, and therefore that 

R x + R 2 = R 3 + R 4 = a -f b. 

If in this equation we substitute the value of R x from the preceding, 
we shall deduce as a consequence, R 2 = R 3 ; that is to say, the engaged 
radii of the wheels on the working shaft are equal when the pistons are 
at the point of nearest approach. 

If two equal and similar ellipses be superposed with their major axes 
at right angles, the points of intersection of their circumferences will 
mark the position of equal radii 5 and this position must necessarily 
bisect the right angle. 

When the semi- axes a and b are given, we may calculate the angle 
made by Ri and R 4 with the major axes of their ellipses, at the same 
moment of nearest approach. The general expression for the square of 
the radius of an ellipse, is 

E 2 — a2 fr 2 

a 1 — e 2 cosV 
in which e represents the eccentricity, and <p is the angle made by the 
radius with the major axis a. 

By measurements made upon a wooden model of this engine placed 
by the side of the engine itself which was in operation in the expo- 
sition building, the minor axis of the ellipses appeared to be to the 
major in the ratio of two to three. By substituting these numbers for 
b and a in the foregoing formula, and putting = 45° we shall find the 
values of R 2 and R 3 to be 2.38 nearly. Then as R x -f R 2 = a + b = 
3 + 2 = 5, we deduce R x = 2.62. 



02 PARIS UNIVERSAL EXPOSITION. 

The general equation transformed gives 

<& (E 2 — ¥) 
C0 ^= We 2 . 
And by substituting the value found for E x in the place of Ri and 
for a and b their values as before, we shall find the value of <p to be 
almost exactly 30°. 

As this angle is reckoned from the position represented in Fig. 16, 
which is the position of maximum relative velocity of the pistons, it 
represents but half the angular movement of the wheel A, or of its cor- 
responding pistons, since leaving the last preceding point of equal velo- 
city. The total movement of A therefore between two such successive 
points, during the period in which its major axis passes the horizontal is 
60°. The relative movement of D during the same time, or its total 
gain on A, amounts to 120°. 

From these computations it results that the pistons should fill 60°, 
each, of the space in the cylinder, and that the vacant space between 
them, when in the position shown in Fig. 17, should be also 60°. The 
larger the disparity between the semi-axes the larger will be this vacant 
space, and the smaller will be the pistons. 

If we consider the expenditure of steam necessary to drive this engine, 
we shall observe that each of these spaces of 60° has to be filled four 
times during each complete revolution of the working shaft ; that is to 
say, eight sectors of the cylinder, having each 60° of arc, must be filled 
in the same time; the whole amounting to one and one-third times the 
capacity of the cylinder. 

Each piston is propelled in the direction of progress through two- 
thirds only of the revolution. If during the remaining third it were 
unacted upon either way, this engine, considering the effect of a single 
piston only, would be only two-thirds as effective, with the same pressure 
and the same number of revolutions, as one exposing the same piston 
surface, and constructed on the plan of Pillner and Hill. But during 
the remaining third it is urged in the opposite direction with the full 
force of the steam. This negative effect must be subtracted from the 
positive, so that in truth the efficacy of the engine is reduced to one- 
third instead of two. On the other hand it has two pistons working 
simultaneously, so that, as compared with a Pillner and Hill, of similar 
piston surface, its performance is as two to three. The expenditure of 
steam being, however, one-third greater, it is economically but one-half 
as efficient. It is recommended nevertheless by its great compactness, 
which adapts it to operations in which economy of space is important: 
and it is stated by the inventor to be already in use in various parts of 
the world in driving machinery, working steam-cranes on shipboard and 
hoisting heavy weights. 

The figures show the manner of admission and discharge of steam 
sufficiently well to require no extended explanation. There are two 
openings at the top, and two at the bottom of the cylinder, oi which 



ROTARY STEAM-ENGINES. 03 

the distance from centre to centre should be exactly equal to the breadth 
of the piston. Through one of these the steam enters, while it is dis- 
charged through the other, as shown by the arrows. A cylindrical valve, 
acting as a kind of two-way cock, shown in cross-section in Fig. 1G, gives 
direction to the entering and escaping steam. This is controlled by 
a crank, shown in Fig. 19. In the cross-section of this valve, Fig. 16, 
is shown its position when the steam is shut off. It is manifest that 
the engine will rotate in either direction indifferently, and that it admits 
of reversal with extreme simplicity. It has, however, four dead points 
in every revolution, and requires a fly-wheel of considerable weight. 
Like most rotaries, it can be used as a water-engine or as a pump. 

THE SOHEUTZ ROTARY ENGINE. 

Mr. Edward Scheutz, of Stockholm^ exhibits a design of a rotary engine, 
of which an idea may be gathered from the accompanying figure (Fig. 20) 
which is a section through the cylinder at right angles to the axis. The 
cylinder itself is contracted on two sides diametrically opposite to each 
other, while the rotating body, a, which carries the pistons, preserves 
its circular form. The pistons are fixed in sockets in which they slide 
freely, being kept in contact with the cylinder by springs placed behind 
them. In passing the contracted diameter of the cylinder, they are 
pressed clown completely into their sockets, and in the wider portions 
they project. There are fixed also, in the cylinder itself, at the extremi- 
ties of the reduced diameter, sliding plates, g and 7i, which are pressed 
inward against the revolving body by springs, so as to maintain there 
always a steam-tight contact. The steam enters at A, passing first into 
a box 0, in which is an oscillating valve of distribution o, employed 
when steam is worked expansively, and controlled by a crank indicated 
by dotted lines at p. This crank is operated by an eccentric on the 
working shaft, shown by the dotted circle at q 7 the connecting rod being 
indicated by the dotted line p q. When steam is used without expan- 
sion, this crank may be thrown out of connection, the oscillating valve 
being placed in position to allow the steam to pass freely from into d ; 
after which it is conducted by passages, which do not appear in the 
section, to the induction openings in the cylinder at i and Jc. The exhaust 
steam leaves the cylinder at I and m and is conducted to e, where it 
escapes into the eduction pipe B. The spaces d and e are openings in 
a slide valve, of which the cross-section is shown, which is moved by a 
lever externally to the machine, and enables the attendant to stop or 
reverse the motion. By means of this slide the steam may be shut off, 
or so directed that I and m may communicate with A, and i and Tc with B. 

There is one other peculiarity which remains to be noticed, and it is 
the only one (except the oscillating valve a, which is unimportant) in 
which this engine differs essentially from a multitude of its class. The 
openings for the introduction of steam into the cylinder, and those for 



94 



PARIS UNIVERSAL EXPOSITION. 



its discharge, are double. The principal openings, i I' J and m, are near 
the diameter of greatest contraction; but these are connected with 
others, u and u'. v and i-', which communicate with the cylinder at points 



Fig. '20. 




ary Steam-engine of E. Scheutz. 



where the contraction begins. The advantage of this is. that when- 
ever a piston, as s, moving in the direction of the arrow, and therefore 
under a full press of steam on the side towards r. passes the point u in 
its progress, the space both behind and before it in the cylinder commu- 
nicates equally with the eduction pipe, and the pressure is relieved. In 
passing further on, therefore, from a to h. the piston is pressed into its 
socket with the minimum of Motional resistance. The same conditions 
exist as the piston returns to its salient position after passing h. This 
advantage is not gained at any expense of motive power, there being 
four pistons 90° distant from each other, while the distance from r to u 
does not exceed 90°. It also follows from this construction that there 
is no dead point, nor is there any dead space. 

On the other hand, it may be observed, that the engine has the fault 
which has been fatal to so many of its kind, of requiring large motion 
of important parts within the cylinder : by which these parts, almost 



ROTARY STEAM-ENGINES. 95 

invariably, work loose. In small models, the advance and recoil of the 
pistons may not be attended with serious evil, but the same can hardly 
be true when these pistons are required to be very large. 

It will be further obvious that the width of the ring, in the direction 
of the diameter of the cylinder, into which the steam is admitted, can- 
not conveniently be made so great, in proportion, as other forms of 
rotary engines allow. It must nevertheless be confessed that there is 
ingenuity and merit in the contrivance for avoiding the excessive fric- 
tion which, in many similar engines, is consequent upon the use of slid- 
ing pistons, and it is, therefore, to be regretted that the engine was 
exhibited only in design, and not in a working model. 

breval's rotary engine. 

Among the many forms of rotary engines which have originated in 
France, but which were not exhibited, is one by Mr. Breval, of Paris, 
which is sufficiently ingenious to merit a passing notice. It is represented 
in cross-section. 1 A is the cylinder. Internally it will be seen that the 
same casting presents two unequal cylindrical bores. B is a cylinder 
revolving within the larger bore, having a diameter exactly double 
that of the smaller cylinder 0, which revolves within the lesser 
bore. These cylinders lit steam-tight, by their }3lane extremities, 
to the ends of the hollow cylinder internally, and they are in inti- 
mate contact with each other during most of the revolution. By a 
system of gear-wheels, external to the cylinder, is made to revolve 
twice as fast as B, so that the surfaces roll on each other without fric- 
tion. B carries two teeth, which are the pistons of the engine, and 
which are fitted to the interior cylindrical surface of A by metallic 
packings. A portion of the cylinder is removed, in order to allow 
the teeth of B to pass. The surface of the recess thus formed is epicy- 
cloidal, so that the tooth maintains close contact with it during the 
passage. The gearing is necessary, in order to insure the presentation 
of this part of the circumference of 0, exactly at the moment when the 
tooth is ready to pass. In order to understand the action of the engine, 
attention should be directed to the positions of the teeth, indicated 
at a and a. Steam being admitted at e behind a, while the cylin- 
ders B and C by their contact prevent escape in that direction, the 
piston is driven forward in the direction of the arrow until it reaches 
the position a'. At this point the steam escapes through c ; and the 
action of the induction valve is such as for a brief interval to -cut off 
the supply at e. But at the same time the other tooth will be passing 
the cylinder ; and this will presently present itself in the position a, 
at which instant the steam will again be admitted. 

] Owing to an accident the wood-cut referred to in this description is wanting, and can- 
not be replaced without stopping the press longer than is desirable. The reference letters 
are retained in the text for convenience of description. 



96 PAEIS UNIVERSAL EXPOSITION. 

The cylinder C has a metallic packing at the points marked d. 

On the opposite or lower side of A, in the mean time, the first tooth 
completes its revolution without further contributing to the propelling 
power. The lower half of the ring has an opening q near the cylinder 
C, which communicates with the atmosphere or with the eduction pipe 
E. so that the pressure is equalized on the opposite sides of each piston 
during the second half of its course. By employing a second cylinder 
like C, at the opposite end of the horizontal diameter of A, both pistons 
might be made effective, and a double power obtained, but it would be 
at a considerable increase of dead space. In the construction shown, 
there is dead space between the horizontal position of the piston and 
the position shown in dotted lines and marked a. This would be doubled 
if a second cylinder should be introduced, since the discharge would 
have to be at q, and at a corresponding point diametrically opposite to 
q, while another induction opening would be required just below c. Two 
pistons would therefore give, while in action, a double power, at the 
expense of a double period of inefficiency,, and a double amount of dead 
space for each. 

The manner in which the admission of steam is managed, so as to 
commence only when the piston is at a. and to cease when it reaches c, 
is shown at o. J is a circular slide valve, which is kept in revolution 
on its centre by the gear-wheel £ and the axis n. Its plane face is in 
contact with the wall of the valve-box, through which there is an 
aperture o' communicating with the interior of the cylinder through e. 
The disk is pierced throughout a considerable part of a complete circle 
with an opening o. So long as this opening is in any manner super- 
posed upon o v , steam will be forced to enter the cylinder : but in the 
position shown in the figure, which is that which the valve has when 
the piston is horizontal, it is the imperforated part of the disk which 
overlies o', and therefore the steam is shut off, and will continue so 
until the extremity of o reaches o' again. It is easily seen that by 
changing this valve disk for one less extensively perforated, this engine 
admits of being worked expansively. The simplicity of its construction 
is greatly in its favor. The principal objection to it is the amount of 
dead space it necessitates: but this is hardly more than exists in the 
Behrens engine. 

boot's double piston squabe exg-lxe. 

One of the most compact forms of steam motor presented by the Expo- 
sition was exhibited by the Eoot Steam-Engine Company of New York, 
and called by them the double-piston square engine though classed by 
the jury among the rotaries. Externally it has the appearance of one, 
rotation seeming to be directly produced without the intervention of any 
perceptible reciprocating or crank motion. By examining the interior, 
this effect is seen to be caused by two pistons rectangular in form, work- 



root's double-piston square engine. 



97 



ing at right angles to each other, and one within the other. Fig. 21 shows 
the arrangement. The larger or external piston is in the form of a rec- 

Fig. 21. 




Root's Double-piston Square Engine. 

tangiilar frame working horizontally within a box of similar form, and 
is marked E. The smaller, marked F, works vertically within E. 
Through the centre of F passes the crank pin, which is carried around 




Fig. 22. 



Fiff. 23. 



in a circle by the simultaneous action of both pistons. The smaller pis- 
ton is shown separately in Fig. 24, and the crank in Fig. 25. Fig. 23 rep- 
resents a plate which closes the steam-box or cylinder, Fig. 21, the sur- 
face presented being that which is external when the plate is in place. 
7ia 



98 



PARIS UNIVERSAL EXPOSITION. 




Fiff. 24. 



The circular chamber shown in Fig. 23 is the valve box, which is closed by 
another plate screwed over it. The steam, which is admitted from above, 

enters at K and is conducted to 
the valve-box by a passage in 
the plate Fig. 23, not seen. 
From the valve-box it is ad- 
mitted to the cylinder through 
the openings marked G, when- 
Fig. 25. ever they are uncovered by the 

valve. Through the same openings the exhaust steam escapes, not into 
the valve-box, but into the annular channel marked H, when the valve- 
plate, which is countersunk on its lower face for this purpose, covers 
them. A single valve-plate serves for the entire distribution. It is 
shown in Fig. 22. Its form is circular, and it has an annular counter- sink 
M on the face applied to the valve face I, designed, as just stated, to allow 
the exhaust steam to escape into H. From H this steam is conducted 
through channels shown in dotted lines to the openings marked H in 
Fig. 21, and thence through channels in the body of the casting to J, or to 
the corresponding point at the other end of the cylinder, where the educ- 
tion pipe is to be attached. The valve plate K is fitted to the eccentric on 
the centre pin D, and this eccentric is carried round by a stud in the 
end of the crank, seen both in Fig. 21 and Fig. 25, which enters an arm on 
the other side of the plate Fig. 23, for which space is made in the central 
circular recess of the smaller piston. The valve is in contact by its cir- 
cumference with the internal cylindrical surface of the valve-box, on 
which it rolls during the revolution, and it opens and closes the steam- 
ports successively as it passes. This contrivance is remarkable at once 
for its simplicity and for its ingenuity. 

The pistons are packed by means of rectangular bars of steel placed 
in grooves on their edges and pressed outward by springs. One of these 
is shown in Fig. 21. 

This engine is without dead points and almost without dead space, 
the pistons working up to the ends of the chamber and to each other. 
with only a slight recess at G, G, Fig. 21, for clearance. 

It is strong in all its parts, not liable to derangement, and of almost 
unexampled simplicity of construction. Of the minor steam-engines it 
is the only one which received from the jury a higher distinction than 
an honorable mention. 

Of its actual performance in practice, an opinion may be formed from 
a statement made by the exhibitors in their illustrated catalogue. This 
statement is to the effect that one of these engines working a pile-driver 
in Xew York raises a weight of 2,200 pounds 36 feet in six seconds, a per- 
formance which is equivalent to twenty-four-horse power, (the statement 
says twenty-two or upward.) The combined piston surface is 56 square 
inches, the length of stroke five inches, and the number of revolutions per 
minute 150. The steam pressure is not given, but with these data and 



ROOT'S ENGINE HYDRAULIC MOTORS. 99 

the observed performance it may be computed. To raise 2,200 pounds 
3G feet in six seconds, indicates a force of 792,000 foot-pounds per min- 
ute. The course of the pistons per minute, making 150 double strokes 
of tive inches each, is 125 feet. The total pressure on the pistons must 
therefore amount to 0,336 pounds, which is equivalent to 113 pounds 
per square inch, or more than 7J atmospheres. And as the observation 
gives, of course, the net horse-power, no account being taken of friction 
in the engine or in the hoisting apparatus, the actual aggregate force of 
the engine ought to be considerably above that just stated, and the 
steam pressure correspondingly greater ; or, say, pressure of eight atmo- 
spheres. This exceeds the ordinary working pressure of steam-engines, 
and hence there would appear to be somewhere a mistake. An experi- 
ment lasting but for six seconds will not ordinarily be timed with suffi- 
cient accuracy to serve as a test of the power of a motor ; and possibly 
the altitude to which the weight was raised may have been assumed to 
be greater than the fact. There can be no doubt, however, of the admi- 
rable performance of these engines, and there seems to be no reason why 
they should not be constructed on a much larger scale than has yet been 
attempted. 

V.—HYDKAULIC MOTORS. 

The usual and generally the most eligible mode of employing water 
power is to apply it to the circumference of some description of wheel. 
Occasionally, however, it may be more advantageous to use it as steam 
is used, for the purpose of moving a piston. This mode of application 
is especially adapted to the use of a small supjfly of water having a large 
fall. 

HYDRAULIC ENGINES. 

Hydraulic engines may be constructed on the plan of steam-engines, 
either reciprocating or rotary. Some modifications will be necessary in 
the construction of the parts, in order to accommodate them to the dif- 
ferent physical properties of the denser fluid. The induction and educ- 
tion pipes, for instance, should be larger than are required for steam,, 
and it is more important also, in this case, that they should have no 
abrupt angles. Freer valve ways also are necessary ; the eduction valve 
should open very promptly at the end of the stroke, and the induction 
valve should not close until the stroke is quite completed — that is to say, 
the influx should cease and the efflux should begin exactly at the same 
moment. Any material error in making the adjustments designed to 
accomplish this end, or any imperfect working of the machinery which 
prevents its attainment, will produce concussions, coups de belter, water- 
ram bloivs, as they are called by the French, which will very certainly be 
injurious and which may be destructive. This is a matter, therefore, 
which requires and receives the inventor's first and most careful atten- 
tion. In the hydraulic engines which have been most extensively intro- 
duced and most successful in practice, provision is made by relief valves 



100 PARIS UNIVERSAL EXPOSITION. 

or other expedients to mitigate or obviate the evil resulting from this 
cause ; but iu so far as it is possible, by the adjustments of the machine 
Itself, to permit the column by which it is operated to maintain a uni- 
form velocity, both true economy of power and durability of parts will 
be best consulted. In the case of steam, attention to the particulars 
here pointed out is not so rigidly necessary ; the difference arising from 
the fact that steam is eminently compressible, while water is so only to 
a degree which for ordinary purposes may be regarded as insensible. 

It is only in some special industries that hydraulic engines have as 
yet been extensively introduced. In the British foundries they have 
been found very convenient and efficient, chiefly in the working of cranes 
and other heavy machinery. They have also been employed occasionally 
for the drainage of mines. A remarkably ingenious illustration of their 
possible usefulness for this latter purpose may be seen at present in ope- 
ration at Huelgoat, in Brittany. The great water engine of Huelgoat, 
the invention of Mr. Juncker, engineer of the mines it is employed to 
drain, has been often described. A very full description is given by Mr. 
Delaunay in his Mechanics. This engine is single-acting, and it acts 
directly to lift the piston of the pump by which the water is drawn from 
the mines. It makes five and a half strokes per minute, the stroke being- 
two and a half metres, or more than eight feet in length. The piston- 
rod is 230 metres (767 feet) long, and it weighs 16,000 kilograms— 1,000 
kilograms being about one ton. The power of the engine is derived 
from a source at a height 110 metres (370 feet) above its own level. 

In this case, though the direct application of the power reduces the 
engine to its simplest form, yet the great inertia of the moving columns 
of water requires that their movements should be very carefully regulated. 
In a reciprocating engine there are moments of rest, and successive 
periods in which the piston moves in opposite directions. When the 
driving force is communicated to a machine through a crank, it is a favor- 
able circumstance that crank motion necessarily retards the movement 
of the piston toward the end of the stroke and brings it insensibly to 
zero; while at the beginning of the stroke it in like manner favors gradual 
acceleration. But in the engine at Huelgoat. without some mechanical 
contrivance to reduce very gradually the volume of inflowing water toward 
the end of the stroke, the piston would reach the limit of its course with 
its maximum velocity, and the sudden arrest of its motion would produce 
a concussion which no strength of materials could resist. The ingenuity 
and the simplicity of the contrivances by which this powerful machine 
is made to regulate automatically its own motions, so as to prevent the 
occurrence of the slightest perceptible shock, has excited the highest 
admiration of every engineer who has examined its construction. 

GARRET, MARSHALL & CO.'S WATER-EXGLXE. 

In the present Exposition the water-engines exhibited are few in num- 
ber. One appears in the British department and two are presented in 



HYDRAULIC MOTORS WATER-ENGINES. 101 

the French. The British engine, which is that of Carrot, Marshall & 
Co., of Leeds, is a cylinder and piston engine having a rather remarkable 
peculiarity. Considering that variations of the velocity of the column 
of water flowing through the machine are necessarily disadvantageous, 
even when unattended with shocks or concussions, since every arrest of 
the flow is attended with the loss of a sensible quantity of living force ; 
and considering that, when reciprocating motion is converted into circu- 
lar motion by means of a crank, the velocity of one or the other of these 
motions must be variable, while irregularity in the circular motion is 
inadmissible, the inventors have dispensed with the crank, and by a 
mechanical contrivance displaying considerable ingenuity have caused 
the force to act always tangentially to the circumference of a disk (or 
rather of a pair of disks) fixed upon the main arbor or working shaft of 
the machine. Thus, as the circular motion of these disks is sensibly uni- 
form, that of the piston may be so likewise, and hence the influx and 
efflux of the water may proceed with an invariable velocity. 

The contrivance by which this application of power is effected consists 
in a pair of toothed racks connected with the piston by a cross-head on 
the top, and constituting a continuation of the piston ; these racks being 
sufficiently far apart to allow the working shaft to pass between them 
without touching. The racks gear into toothed sectors which receive 
from them a reciprocating motion, and which are furnished with a sys- 
tem of clamps which lay hold on the disks above mentioned when the 
motion corresponds with that of the revolution of the shaft, but release 
them when it is in the contrary direction. The admission of the water 
alternatively above and below the piston is effected by a slide-valve ope- 
rated by a rod carried by the piston itself ; and the flow of the water from 
the source is sensibly uniform in velocity not only during the stroke but 
during the change of direction of the piston. The object aimed at, viz., 
the prevention of shocks, is thus perfectly secured, provided the piston 
and the apparatus connected with it be light. The construction is there- 
fore sufficiently well adapted to engines of small power, although the 
mode of securing circular motion seems to be unnecessarily complicated. 
In the engine exposed, the nominal power is one-sixth of a horse-power, 
the cylinder being five and a half inches in diameter, the stroke ten inches, 
and the water pressure three atmospheres. The price of such an engine 
is stated at 1,080 francs, or about $200. The inventors undertake to con- 
struct engines on the same model, of any desired power or dimensions. 
They give a list of dimensions and prices, which embraces a range of 
from two to seven inches in the diameter of the cylinder, and in which 
the prices vary from 600 to 1,640 francs. For movements which do not 
require transformation of reciprocating into circular motion, these little, 
machines must be very useful, wherever a small stream of water is avail- 
able with a pressure above that of the atmosphere. Thus they may be 
applied to the blowing of bellows for organs or for forges, to the working 
of pumps, the sawing of wood or stone, to polishing marble or glass, and 



102 PARIS UNIVERSAL EXPOSITION. 

to many similar purposes. They are recommended by their neatness 
and safety, and also "by their comparative cheapness. 

perret's water-engine. 

A reciprocating water-engine is presented in the French section of 
the Exposition by Mr. F. E. Perret. This is the most remarkable 
machine of the kind exhibited; and it has been thought worthy of a 
medal by the jury. Its construction presents some novelties, which 
hardly at first view produce a favorable impression. The essential parts 
of the engine are a cylinder and a double-acting piston. The motion is 
communicated to a working shaft in the ordinary way. The peculiari- 
ties consist in the manner of admitting and discharging the water. 
This is effected through openings at each end of the cylinder which 
occupy the greater part of its circumference and form a sort of annulus ; 
there being left only enough solid metal to connect the end of the 
cylinder with the body. Thus the water is admitted to the interior from 
all sides. To facilitate this, the cylinder is entirely enveloped by a 
second cylinder, with a space intervening between the two, which is 
filled with the water of induction. The extreme portions of the work- 
ing cylinder are turned very smooth externally in a lathe, and the ends 
of the enveloping cylinder are here contracted, and turned likewise on 
the inside, so as to make a joint as nearly as possible water-tight. Both 
these cylinders are* enveloped completely by a third and larger one, 
between which and the second, there is a space for the escape of the 
water on its discharge. This cylinder and the secondare cast in a single 
piece, and form one body. The extremities of the third, like those of 
the second, are adapted accurately to the surface of the first, but there 
is a space between the second and third at this surface, which is as 
wide as the annular series of openings above described in the first, by 
which the water is to be admitted into or discharged from the first, 
which is the working cylinder. It is obvious from this disposition of 
things, that in order that the machine may operate, either the inner 
cylinder must move backward and forward alternately, so as to present 
the openings which answer to its valves in front of the spaces which 
communicate with the supply and exhaust : or that the two external 
cylinders should move in this manner, while the inner one remains 
fixed. Mr. Perret has chosen the first of these methods, apparently 
because it presented fewest difficulties. But for an engine on a large 
scale, either seems objectionable. 

The motion of the working cylinder through the small space which is 
required to effect the admission and discharge of The water, is accom- 
plished by means of an eccentric upon the crank shaft, which is set at 
right angles to the crank, and 90° behind it in the direction of revolu- 
tion ; so that the motion of the cylinder is in a direction contrary to 
that of the piston in the first half, and in the same direction in the last 
half, of the stroke. The breath of the annular opening is exactly equal 



perret's water-engine. 103 

to that of tlie metal which separates the supply from the exhaust in the 
exterior cylinders ; audit will be seen that the working cylinder itself 
performs the function of the slider in the valve box of the steam- 
engine. It happens accordingly that there is no interval between the 
shutting off of the supply and the commencement of the discharge ; but 
that the efflux begins the moment the influx ceases. 

It would be difficult to judge of the practical usefulness of a machine 
of novel character, from the imperfect opportunities which are afforded 
to study its working in a place like the Exposition. Fortunately, how- 
ever, this particular engine has been made a subject of very elaborate 
theoretic discussion and experimental study by a very competent critic? 
M. Ordinaire de Lacolonge, who has published an extended paper on 
the subject in the Annates du Conservatoire des Arts et Metiers, and 
whose conclusions in regard to it are summed up succinctly in the fol- 
lowing propositions : 

The performance of the machine is better at low than at high veloci- 
ties of the piston. 

When the motion of the piston is about one metre per second, the 
performance is equal to that of other good hydraulic motors ; that is, it 
is above 60 per cent, of the hydraulic power expended. 

The machine cannot be advantageously employed with water carrying 
sand. 

This water-engine is especially adapted to the utilization of small vol- 
umes of water having a large fall. 

And it may be further added that the machine may be placed at a 
point intermediate between the source and the level of final discharge, 
with the full effect due to the total head, provided the discharge be 
through a tube continued to the lower level, and of such form that air 
shall not enter it from below. 

Mr. Perret exhibited two of his motors in the Exposition, one of which 
was mounted as an oscillating engine. This form is exceptionable on 
account of the large lateral friction which it introduces between the 
external and internal cylinders. The other was employed to drive a 
rock-perforator, the invention of Mr. De la Eoche Tolay, a French engi- 
neer, which itself excited a good deal of interest, being the machine 
known as the "diamond perf orator." In this machine the perforating tool 
consists of a soft iron ring fitted to the extremity of a steel tube from 
which it may be removed at pleasure, and carrying eight black diamonds 
firmly set in its circumference. These eight diamonds are set alternately 
on the inner and outer edges of the face of the ring which is presented 
to the rock. The mineral called here black diamond, is essentially the 
same thing as the transparent gem of the same name, but is of greatly 
inferior value. It is found both crystallized and uncrystallized j but, for 
the purpose required in this operation, the uncrystallized form is pre- 
ferred, as presenting no natural cleavages. The mineral is sold by 
weight, its cost being proportioned to the weight simply, and not to the 



104 



PARIS UNIVERSAL EXPOSITION. 



square of the weight, as is the case with the precious diamonds. The 
cost of a ring, such as is described above, is 175 francs, or $35. 

The diamond perforator penetrates the rock, of course, by friction and 
not by percussion. It receives, therefore, from the motor a motion of 




LJ 



Perret's "Water-engine. 



ferret's water-engine coque s engine. 



105 



rotation, being pressed in the meantime firmly against the rock by 
hydraulic pressure applied through a second independent cylinder and 
piston. The experiments which have been made with this perforator 
give results which promise important economical advantages from its 
use in rock-boring. Some of these results are as follows : 

Under a pressure of eight atmospheres, 100 turns of the perforator per 
minute give : in old mica schist, containing little quartz, 1.2 inch ; in 
similar rock, with much quartz, 0.4 inch to 0.6 inch ; in quartz from the 
tunnel of Mont Cenis, 0.56 inch ; in very hard dolomitic limestone 0.8 
inch. 

Under the same pressure, increasing the number of turns of the perfo- 
rator from 100 to 250 per minute, the advance is very exactly twice and 
a half as great as before, showing that the effect is proportional to the 
velocity. 

In order to produce a velocity of 100 rotations per minute, an expen- 
diture of seventy-five litres, or about twenty gallons of water, was neces- 
sary in these experiments. 

The inventors expect to be able to reduce the expense of rock-drilling 
seventy-five per cent, upon the present actual cost after the apparatus has 
been once set up. The application of the hydraulic motor would, however, 
be attended with only a moderate economy if it should be necessary to 
raise the water which is required to drive tne engine by artificial means 
to a suitable level. 

The construction of the engine, above de- Fig. 28. 

scribed, will be understood from an examina- 
tion of Figs. 26, 27, and 28: 

A, (Fig. 26,) is the inner cylinder. B B mark 
the external cylinder, and O C the intermedi- 
ate. P is the piston just beginning to des- 
cend. The arrows show the openings for en- 
trance and discharge of water. I is the 
induction pipe, and E the eduction pipe. D 
D are prolongations of the working cylinder, 
in smaller diameter, to allow it to slide for- 
ward and backward. The piston rod p passes 
through a stuffing-box s, at the end of D 7 . 
There are also stuffing boxes at t and V. 

Fig. 27 is a view of the engine in plan, and 
Fig. 28 is a section through G H, in which the 
relation of the induction and eduction pipes 
to the external and intermediate cylinders is clearly shown. 

coque's water-engine. 

A third form of water-engine was exhibited by Mr. A. Coque, of Paris. 
This is also reciprocating, and its peculiarities consist in the operating 
of the induction and eduction valves by means of a cam on the working 




106 



PARIS UNIVERSAL EXPOSITION. 



shaft instead of an eccentric, in consequence of which arrangement the 
change is made abruptly at the end of the stroke; and in the admission 
of a small amount of air along with the water, by means of which the 
danger of a hydraulic concussion is obviated. This last feature is not 
without importance, as it removes one of the greatest difficulties in the 
way of the successful operation of water-engines. 

The inventor represents that, in case of a deficient supply of water, 
the quantity of air admitted may be increased ; for which purpose he 
employs a second valve, capable of adjustment to the quantity required. 
In this case, the air, which is admitted before the water, is first com- 
pressed 5 and it afterwards reacts by its own elasticity, so that the engine 
has to some extent the double character of a water and of an air engine. 

The machine exhibited is in dimensions hardly more than a model, the 
diameter of its cylinder internally being only thirty-one millimetres, or 
an inch and a quarter, and the length of stroke 162 millimetres, or six 
and a half inches. Its performance yields about sixty-four per cent, of 
the power applied. Under a pressure of twelve metres of water (nearly 
an atmosphere and a quarter) and with sixty revolutions per minute, it 
furnishes actually about one-eighth of one-horse power. On a larger scale 
the result might probably be still more satisfactory. 

RA3ISBOTT03TS WATER -ENGINE. 

None of the water-engines exhibited seem to possess the merit of those 
of Messrs. Eamsbottom & Co., of Lancashire, England, which are so exten- 
sively in use in the British 
foundries : and some sur- 
prise was felt that these 
engines were not repre- 
ented in the Exposition. 
The following brief des- 
cription of one of the 
Eamsbottom engines is here 
introduced for the purpose 
of comparison: 

The engine is oscillating, 
and employs two cylinders 
operating the same work- 
ins: shaft bv means of two 



cranks at right angles to 
each other. The cylinders 
are supported in a stout 
framework of cast-iron. 
The details of construction 
may be best understood by 
RaiiisbottoHi's Water-engine. reference to the accompa- 

nying figures. Fig. 29 is a section through the cylinders, which arc 




RAMSBOTTOM'S WATER-ENGINE. 



107 



Fig. 30. 




vertical, and shows the mode of suspension of the cylinders, and the 
channels of induction and eduction, which are marked j, and which 
are cast with the cylinder. The dotted 
circle c shows the position of the supply 
and discharge pipes. Fig. 31 shows a 
cross-section of the cylinders and their 
pivots, and in this will be seen the places 
of attachment of the pipes just men- 
tioned at K and K. The pivots are of 
steel. Those intermediate between the 
cylinders are firmly fixed in the support. 
The external pivots admit of adjustment 
by means of the screws and screw-nuts d 
and /. Fi g. 30, which is a section through 
the line 1 and 2, Fig. 29, shows the system 
of water distribution. The apertures of 
induction and eduction are represented 
at h and i 7 and have the form of trun- 
cated circular sectors, whose centre is 
the centre of motion. The spaces marked 
li are divided from tliose marked i by 
a sectoral partition, which is of pre- 
cisely the same area in cross-section Ramsbottom's Water-engine. 
as they. The apertures of admission and discharge on the side of the 
cylinders are also of the same form and dimensions. The surfaces of 
contact between the cylinders and the support D are perfectly plane 
and polished, and are made water-tight by means of the adjusting screws 
d and / of the pivots. When the piston is at the end of its course in 
either direction, the cylinder will be truly vertical. In this position the 
piston is momentarily at rest, and both induction and eduction valves 
should be closed. Accordingly the dispo- 
sition of the parts is such that, when the 
cylinder is vertical, the openings by which 
the channels j j communicate with the 
supply and discharge pipes present them- 
selves exactly opposite to the solid sector 
dividing h from i. In the next moment 
the flow of water will recommence, the 
cylinder discharging itself from the full 
side of the piston, and filling anew on the 
opposite side. Fig. 31 . 

From this statement it is apparent that the influx and efflux of the 
water proceeds with more and more freedom from the beginning to the 
middle of the stroke, when the passages are at their maximum opening, 
and that from this point to the end the reverse takes place. But it is to 
be also observed that, from the nature of crank-motion, the velocity of 




108 PARIS UNIVERSAL EXPOSITION. 

the piston varies correspondingly, and that the relation of the supply of 
water to the demand is very nearly constant. 

Very nice adjustment is evidently necessary in these engines, in order 
that the moment of the absolute closing of the valves may correspond to 
that of the completion of the stroke ; and as it is possible that this 
perfect coincidence may not be exactly secured or permanently main- 
tained, some provision against counter-pressure and the effects of 
hydraulic shocks is necessary. Air chambers and relief valves are 
employed for this purpose. The relief valves open a backward commu- 
nication between the cylinder and the driving column, so that if there 
occurs an obstruction to the discharge, the pressure on the two sides 
of the piston will be equilibrated by the opening of the valve. 

The engines constructed by Messrs. Eamsbottom on this model are 
generally small, some of them having cylinders of not more than two 
inches in diameter. They have been used for a variety of industrial 
purposes, as for operating printing presses, circular saws, lathes. &c. as 
well as for cranes and other machinery in foundries. Their simplicity 
and neatness render, them preferable to almost any other form of small 
motor, wherever the hydraulic head can be easily secured for working 
them. But in general it is not a natural hydraulic head that is depended 
on, and indeed no natural head could furnish, in maehiues of so small 
model as those employed in the British foundries, anything like the 
large power which they exert. The head is established in an accumula- 
tor of power, which is a body of water driven into a reservoir under 
heavy pressure, by forcing pumps worked by steam. For lighter indus- 
tries such expedients are unnecessary. In cities in which the water 
distribution is from elevated reservoirs, and in which the water supply is 
sufficiently abundant to justify the application of a portion of it to 
industrial uses, the water-engine is recommended by the combined 
advantages of simplicity, neatness, compactness, constant readiness for 
work, perfect safety, economy while working, and the absolute cessation 
of expenditure during interruptions and after the work of the day is 
over. 

WATER-WHEELS AND TURBINES. 

One of the most striking objects in the section of the park allotted to 
France in the Exposition, was a model of one of the six great water- 
wheels constructed at Marly by order of the Emperor for the purpose of 
driving the water-works which supply the city and palace of Versailles. 
These wheels are twelve metres (about forty feet) in diameter, con- 
structed of iron, with plane wooden floats. They present no nov- 
elty in principle, but are magnificent specimens of workmanship. The 
only water-wheels exhibited which embraced any novelty were those oi 
Mr. Delnest, of Mons, and of Mr. Sagebien, of Amiens. 

The wheel of Mr. Delnest has great breadth compared with its diam- 
eter, and is provided with floats called helicoidal. These are in tact 



WATER-WHEELS AND TURBINES. 109 

nearly plane, but are slightly winding, screw-shaped, upon the cylin- 
drical body of the wheel, so that the two opposite ends form contrary 
screws which meet in the middle line at an obtuse angle. As the wheel 
turns, the angle meets the water first, and according to the inventor the 
inclination of the two sides facilitates the escape of air. ^No experi- 
mental results of the performance of this wheel were given. 

The other wheel mentioned, that of Mr. Sagebien, which is designed 
as a kind of breast wheel, is provided with plane floats, very deep rela. 
tively to the wheel, (about one-third of the radius,) and inclined so as to 
enter the water by their outer edges first. After the immersion of the 
edge, therefore, there will be an enclosed space between the float and the 
cylindrical surface of the wheel which, unless the velocity of rotation 
were very slow, would be liable to retain a certain amount of air. This 
velocity is, however, designedly kept low, and a large diameter is given 
to the wheel, by which means the water, acting by its weight upon a 
long radius, imparts great power and expends nearly all the work that 
is in it in making the descent. The wheel works very near to the walls 
enclosing it, and the waste by escape is not considerable. The actual 
velocity at the circumference is but about two feet or two and a half per 
second, while the entire circumference is from seventy -five to one hun- 
dred feet, so that it turns hardly more than three times in two minutes. 
It is to be said in favor of this wheel that it economizes the driving 
power to a remarkable degree, yielding not less than seventy per cent, 
of the total. On the other hand, its revolution is so slow that for most 
purposes it is necessary to employ accelerating wheel work to a greater 
extent than is required by most motors, so that the economy is partially 
balanced by increase of friction, greater complication of machinery, 
larger cost for the original constructions and occasional repairs, and 
correspondingly increased liability to derangement. 

Mr. Colladon, of Geneva, exhibited in the Swiss department a wheel 
adapted for use on streams whose natural current furnishes a sufficient 
power to be made available without a dam, and which also are liable to 
considerable changes of level. This is called a floating wheel, from the 
fact that the construction permits it to follow the elevations and depres- 
sions of the water as occasion may require. Although the wheel is thus 
movable, the machinery which it moves is fixed ; and the peculiarity 
consists only in the connections which permit the transmission of the 
power in all the changes of its position. It is an expedient which in cer- 
tain situations may be useful as being the only one available, though not 
suited to furnish a very large amount of power, nor that, in theory, very 
economically. 

The hydraulic motors which in general furnish the largest useful effect 
in proportion to the living force of the water which passes through them, 
are the class called turbines. The theory of the turbine was ably inves- 
tigated by Euler, but its practical realization was not accomplished until 
1832, which is the date of the invention of the motor known as the " tur- 



110 PARIS UNIVERSAL EXPOSITION. 

bine Fourneyron." Euler's idea was to construct a horizontal wheel to 
turn on a vertical axis, and to be driven by water directed from a 
reservoir immediately over it, upon floats of curved form fixed to its 
circumference. The curvature to be given to the floats was such, that 
at the top, where the impulse of the water was to be first received, they 
should be nearly vertical, while at the bottom they should approach the 
horizontal. Within the reservoir he proposed to place a set of curved 
plates to give direction to the issuing water, in which the construction 
above described should be reversed, the summits of the directrices being 
nearly vertical, and their lower edges nearly horizontal. By this arrange- 
ment it would happen that the water at its first discharge would strike the 
faces of the floats or pallets nearly in the plane of rotation ; and before 
its final escape, it would transfer to the wheel nearly all its living force. 
No water from the reservoir was to be admitted to the wheel except that 
which was directed on the pallets. 

fourneyron's turbine. 

The Fourneyron turbine was a departure from Euler's plan, but it was 
conformed to the general principles of his theory. The water from the 
source was admitted into a cylinder of small diameter, closed at the bot- 
tom. In the middle of this cylinder was fixed a still smaller one, through 
which the axis of the turbine ascended, being thus protected from con- 
tact, with the water which was confined to the annular space between the 
two. The turbine itself was a horizontal disk running close to the bottom 
of the cylindrical reservoir, but larger in diameter ; its floats being fixed 
to the perimeter of its upper surface, and forming a riug which sur- 
rounded the bottom of the reservoir. The apertures for the efflux of the 
water were therefore placed in the cylindrical surface of the reservoir, 
opposite to the floats, and the escape was as nearly as possible tangential 
to this surface. The manner of opening and closing these apertures of 
escape was by means of an interior cylinder accurately fitting the main 
cylinder of the reservoir, and this was lifted and shut down by mechani- 
cal contrivances operated by the attendant from above. Other turbines, 
more nearly on the plan of Euler, have since, to a great extent, super- 
seded the turbine of Mr. Fourneyron. To understand their peculiarities, 
and to be able to judge of their respective merits, it is necessary to attend 
to two or three preliminary considerations. 

A turbine wheel Avill run though entirely immersed in the water ; 
but it will perform best if kept free from contact with all water except 
that which is employed in propelling it. 

As the supply of water varies, or as the work which the wheel is 
required to do is greater or less, it is desirable to enlarge or diminish the 
amount of water admitted to the wheel. There is of course a certain 
maximum amount which cannot be exceeded, and this will be the amount 
received by the wheel when all the orifices of discharge are fully open. 
This maximum may be reduced in either of two wavs : First, the size of 



fourneyron's turbine— girard's turbine. Ill 

each one of the apertures of discharge may be partially reduced ; a result 
which may be obtained in the Fourneyron turbine by depressing more 
or less the internal cylinder which forms, as above stated 1 / the gate ; or, 
secondly, a larger or smaller number of the openings may be entirely 
closed while the remainder are left open to their full extent. The first of 
these methods was employed by Mr. Fourneyron, but experience has 
proved that it is disadvantageous. The floats are not filled, and the 
water escapes without having fully expended its force against them. In 
order to meet this difficulty, Mr. Fourneyron divided the water space 
between the floats by means of horizontal partitions, so as to form three 
sets of cells having the relative capacities, one, two, and three. This 
allowed the gate to be raised to three different heights, but did not pro- 
vide for intermediate elevations j and it increased also the proportional 
amount of frictional surface. In the more recently constructed turbines 
the problem has been resolved in a more general manner. 

In order to secure the largest benefit from the given fall of water, it is 
desirable to place the turbine as low as possible. This is inconsistent 
with the condition of best performance mentioned above, which requires 
that it should not be immersed, unless at least some means can be con- 
trived by which it may be made to run in air, although beneath the sur- 
face of the water at the foot of the fall. 

THE GIRARD FREE TURBINE. 

The most striking improvement which has been made in connection with 
the turbine* wheel since the earliest industrial application of the machine 
by Mr. Fourneyron, is one by which the important object just mentioned 
has been effectually secured, and is due to Mr. Girard, of Paris, who has 
also in many other ways perfected this important machine. This con- 
sists in adapting to the lower part of the water cylinder an air chamber, 
open at the bottom, which encloses the wheel, and from which the water 
is excluded, whatever may be the level in the natural channel without, 
by condensing the contained air to a suitable degree of elasticity. For 
this purpose a small air-pump, worked by the machine itself, is employed 
to throw air into the chamber in order to supply the loss which may 
occur by leakage, which is inconsiderable. The level of the water is thus 
kept constantly below the lower extremities of the floats of the wheel, 
whatever may be the changes of natural level. To prevent the loss 
which might arise in consequence of the entanglement of bubbles of air 
in the water escaping from the wheel, an expedient is adopted which is 
at once ingenious and effectual. The water which escapes, instead of 
being left free to mingle at once with that of the stream below, is kept 
confined within an inverted trough for a sufficient distance to allow the 
air which is mechanically mingled with it to rise to the top, when it is 
received into a bell-shaped chamber, which arrests its further progress. 
A tube connecting this chamber with that enclosing the wheel, returns 
it by the mere effect of hydrostatic pressure. 



112 PARIS UNIVERSAL EXPOSITION. 



THE FONTAINE TURBINE. 



Turbines on the plan of Euler were first introduced by Mr. Fontaine, 
of Chartres. Examples of the Fontaine turbines were exhibited by 
Messrs. Brault and Berouard, also of Chartres. In the original construc- 
tion of Mr. Fontaine the water was admitted to the floats of the wheel by 
a system of small sliding gates or valves, each opening being provided 
with a separate gate, but the whole being raised and depressed together. 
The wheel itself was immediately and entirely under the cylindrical 
water chamber ; its extreme diameter, from out to out, including the 
floats, being the same as that of the reservoir. The water openings 
formed therefore a ring arranged around the circumference of the water 
cylinder, and were pierced through its bottom, and not, as in the turbine 
of Fourneyron, through the sides. But as the form of the directrices 
was such as to be nearly vertical at top, and horizontal at bottom, the 
lower lip of each of the directing plates was almost vertically under the 
upper edge of the one next following ; so that a valve sliding vertically 
could close the channel of discharge, without intersecting either of the 
bounding surfaces in such a manner as to produce any obstruction to the 
water by irregularity of flow or increase of friction. As all these valves 
were raised and depressed together, the quantity of discharge could only 
be varied, as in the case of the turbine Fourneyron, by raising them par- 
tially or wholly, according to the exigency. But this method was 
attended with a disadvantage similar to that indicated in the former case. 
The action of the water on the floats was not favorable unless they were 
fully filled. In the case of the Fourneyron turbine, when the water was 
but partially turned on, it was received on but a part of the breadth of 
the float ; in the present case it was received on the entire breadth, but in 
a thinner sheet. The effect, however, was practically the same : to which 
it may be added, that the frictional resistance opposed to the issuing 
water in the Fontaine turbine, when the valves were but partially opened. 
was considerably greater in proportion to the whole force than when the 
passages were entirely free. 

TURBINES OF BRAULT & BETHOUAED. 

The more recent improvements of the turbine have been concerned 
mainly with the construction of these valves. Vertical sliding valves 
have been generally abandoned. In the turbines of Messrs. Brault & 
Bethouard, the valves are simply covers formed of gutta-percha, strength- 
ened by metal plates, each of sufficient size to close one orifice. These 
valves are connected together in a manner to facilitate the control of 
them, and are in two separate sets. The mode of control will be under- 
stood by considering that the orifices to be closed form a regular ring. 
If we cut a ring of the same figure out of paper, and. laying it flat upon 
a table, place upon it a cone, with the vertex truly at the centre of the 
ring, and then cutting the paper in the direction of the radius, attach 



HYDRAULIC MOTORS — TURBINES. 113 

one of the cut ends to the surface of the cone by means of some adhe- 
sive substance, we shall be able, by merely rolling the cone on the table, 
to take up the entire ring, and by reversing the direction of the rolling, 
to lay it down again ; the vertex of the cone in the meantime maintain- 
ing its position at the centre where we originally placed it. This is the 
expedient adopted for opening and closing the water passages in the 
turbines here spoken of, only that two cones are employed instead of 
one. It is only necessary to suppose in the illustration just given, that 
to the surface of the ring of paper there are pasted a number of fan- 
shaped bits of stiff card-board, all equal to each other, and we shall have 
a representation of the valve system of Messrs. Brault & Bethouard. 
It is only necessary to add that the end of the ring not secured to the 
cone must be fixed to the interior of the water chamber. This system, 
it will be seen, will allow the quantity of water admitted to the wheel to 
be increased or diminished at pleasure, while all the orifices which are 
opened at all are opened entirely. It has been mentioned that there are 
two cones employed in the manner described. This is partly in order 
to direct the action of the water symmetrically on the circumference of 
the wheel, and partly because in this form the apparatus is neater. A 
single cone for the whole circle would moreover require to be larger, and 
would, therefore, interfere to a greater degree with the access of the 
water to the openings which happen to be near it, a disadvantage which 
is to some extent true of the actual construction. Another disadvantage 
of this construction is, that in case foreign substances are brought along 
by the water and lodge in the passages, the valves fail to shut closely, 
and water is lost by leakage. 

In several other turbines exhibited the valves were constructed with 
hinges, and the mechanism controlling them was designed with a view 
to vary at pleasure the number open. These answer perfectly the pur- 
pose intended when the water is entirely clear, but they are liable to the 
objection in regard to obstruction which has been made to the system 
last described. 

protte's turbines. 

Mr. Protte, of Vendeuvre, (France,) exhibited one turbine in which 
all the orifices of discharge in an entire semicircle are closed by one flat 
sliding cover in the form of a ring. By giving to this ring a sliding 
motion, having as its centre the centre of the reservoir itself, a larger or 
smaller number of the orifices of discharge can be opened at pleasure. 
It is apparent, however, that if, as in the ordinary construction, the 
whole circumference of the water chamber were occupied by these ori- 
fices, it would be impossible to uncover, by means of such a sliding semi- 
circle, one aperture, without closing another. Mr. Protte endeavors to 
get rid of this disadvantage by placing the discharge orifices of one- 
half of the circle nearer to the centre than those of the other half. He 
has, therefore, a second semicircular cover, which is a portion of a ring 
81 A 



114 THE UNIVERSAL EXPOSITION. 

of less diameter than the first. By means of these two, all the openings 
can be controlled, and a greater or smaller number uncovered at plea- 
sure. It follows, of course, that the directrices of the water correspond- 
ing to the second set of openings just mentioned, must be so constructed 
as to convey the water to some extent in a radial as well as in a lateral 
direction. In the changes of direction and increase of friction thus 
introduced, there is some disadvantage, but the system of water control 
is undoubtedly preferable to any of those previously described. 

girard's improved turbine. 

Mr. Grirard has constructed turbines designed to admit the water only 
on two opposed quadrants of the circumference. In these, the system 
of sliding valves just described (which was first introduced by him) 
admits of being used, without being liable to the objection pointed out 
as attending that ; since each annular valve cover, being but ninety 
degrees in extent, may be turned entirely off from the group of open- 
ings to which it belongs, without encroaching on those of the opposite 
group. 

Another method employed by Mr. Grirard to secure effectually the 
control of the discharge of the water, and at the same time to utilize 
the whole circumference of the wheel, is to close the apertures of dis- 
charge by slides which move outwardly in a radial direction. But, 
inasmuch as there is always liability to obstruction, from the intrusion 
of the debris of vegetation or other matters borne along by the stream, 
when the apertures are small, he prefers in many cases to admit tbe 
water only to a part of the circumference, a third for example, or a 
fifth, and to leave all the rest of the wheel uncovered ; which construction 
allows access to the floats, permits obstructions to be removed without 
difficulty, and greatly facilitates the execution of any necessary repairs. 
As a compensation for the smaller number of floats acted upon, he 
makes the apertures larger, and increases the diameter of the turbine 
at the same time. These machines are called by him " lateral-injection 
turbines." 

rteter's turbine. 

Several other lateral injection turbines were on exhibition. One of 
these, by Mr. Eieter, of Switzerland, was without any system of direct- 
rices. The tube which conducted the water to its circumference formed 
a kind of box embracing only about a quarter of a circle, the remainder 
of the wheel being free. It was said to give a return of seventy per 
cent, of the force applied. 

schiele's turbine. 

Another, exhibited by the North Moor Foundry Company of England. 
the invention of Mr. Schiele, possesses the great merit of extreme simp- 
licity of construction, of entire accessibility at all times, and of utilizing as 



HYDRAULIC MOTORS SCHIELE 7 S TURBINE. 



113 



large a proportion of the power as the best Fourneyron or Girard tur- 
bine. This also is a lateral injection turbine, and requires no other 

Fig. 32. 



illlll ■!.;; ;,■!! I !>; :-f .M) - '.'.lUl'lll • Ill 




Schiele's Turbine. 

directrix for the water but the tube of supply. Its construction will be 
understood by referring to the figures. It is enclosed in a cylindrical box 
which is open both above and below, and which serves only to guide the 



116 



PAEIS UNIVERSAL EXPOSITION. 



water as it enters by the lateral pipe shown in Fig. 32 in elevation, and 
in Fig. 33 in i)lan. The construction of the wheel itself is seen in Fig. 34. 




Scbiele's Turbine — plan. 



Fisf. 34. 




The floats have such a form as may allow 
the water to expend its force in giving ro- 
tary motion to the wheel, and finally to 
escape in a direction up or down nearly 
parallel to the axis. 
t The figures represent the Schiele turbine 
I as placed in the ordinary position with the 
axis vertical. But it works equally well with 
the axis in a horizontal position : a fact not 
equally true of ordinary turbines. This, 
however, is often a great advantage in the 
application of power ; permitting such an arrangement as may make 
the application direct, whatever may be the nature of the work to 
be done. Another great advantage is that it may be placed at any 
level between the head and foot of the fall, and yet make available 
the force due to the entire head. In order to do this, however, the 
wheel must, of course, be wholly enclosed, and the water which leaves 
it must be conducted down to the lowest level in a continuous tube, 
where it must either be recurved to prevent the admission of air. or. 
what is better, be immersed in the water of the stream below. Under 
these circumstances it acts by its weight on the wheel, precisely as. sup- 
X^osing the top of the tube to be closed by a piston, and the water above 
the wheel to be without weight, this water below would still drag down 
the piston with the same force with which it would press it if it wore 



HYDRAULIC MOTORS — TURBINES — THE DAN AID. 117 

introduced above. Some of the turbines of this company have been 
established at points thirty feet above the foot of the fall by which they 
are driven. This is an important advantage in respect to the application 
of force, and may often serve to render complicated systems of transmis- 
sion unnecessary. 

It should be mentioned, however, that the ordinary turbine is capable 
of being employed in the same manner, at a point chosen at pleasure 
between the highest and lowest level. The construction adapted to this 
mode of employment is commonly called the Jouval turbine ; but it has 
no peculiarity to distinguish it generically from the turbine of Fontaine. 
The wheel is simply enclosed hermetically, and a tube is continued, as 
above described, to the lowest level. 

THOMPSON'S TURBINE. 

An additional form of the turbine was exhibited by Messrs. William- 
son, Brothers, of Kendal, England, the invention of Mr. Thompson, of 
Glasgow. The peculiarity of this consisted in the admission of the 
water horizontally at the circumference of the wheel, and permitting it 
to escape, after having expended its force, at the axis. This is what 
may perhaps be called the Fourneyron turbine inverted. The floats or 
pallets of this wheel are proportionally longer, measured in the radial 
direction, than those of the turbines constructed on the principle of 
Euler, and they have a contrary flexure towards the centre. It is a dis- 
advantage of this mode of applying the power, that the wheel cannot 
be enclosed in an air chamber according to the plan of Mr. Girard, but 
must necessarily be always immersed. The construction has also been 
criticised, on the ground that the centrifugal force which will be imparted 
to the water by the rotation of the machine will act in direct opposition 
to the driving column, and will to that extent neutralize its power. But 
it is to be considered, on the other hand, that the pressure thus seem- 
ingly lost is expended in forcing the rotating water nearer to the centre 
of the wheel, where its angular velocity is greater than that of the pal- 
lets, and where consequently it transfers its moment of rotation almost 
wholly to the wheel. Whatever amount of rotary motion is given by 
the wheel itself to the water is of course lost entirely in the ordinary 
turbine. If this can be by any contrivance retransferred again to the 
wheel, a compensation will be effected. The fact that the resistance 
opposed by the centrifugal force of water revolving within a wheel to 
the pressure of the propelling column is not a source of loss when the 
pressure drives the revolving water to the centre, is practically demon- 
strated in the hydraulic machine called the danaid, invented by d'Ectot. 

THE DANAID. 

The danaid may be described as being formed of two hollow cylinders 
placed concentrically one within the other, and enclosing a small space 
between them. The inner cylinder is closed at the bottom j the outer has 



11.8 PAEIS UNIVERSAL EXPOSITION. 

an aperture in the bottom at the centre. Between the two bottoms 
there is a space of an inch or two, in which are placed a number of 
partitions extending from the central aperture to the circumference, 
which prevent the possibility of a rotation of the vessel without carry- 
ing along with it any liquid which may be between them. But the 
annular cylindrical space is without partitions. The contrivance being 
placed in a vertical position, and sustained by an axis permitting tree 
revolution, water is introduced into the annular cavity through one or 
more pipes proceeding from an elevated reservoir, and directed, at the 
orifice of discharge, as nearly tangentially as possible to the cylindrical 
surface. Rotary motion is imparted thus at first to the machine by 
mere friction 5 but as the velocity increases, the centrifugal force tends 
to resist the discharge at the central orifice. The pressure of the col- 
umn, however, prevails over centrifugal force, and the rotating water is 
driven constantly toward the point of discharge, imparting of necessity 
the living force which it had acquired by revolution to the vessel itself, 
by pressing laterally against the partitions. 

In a series of experiments made in 1813 by Messrs. Prony and Carnot, 
of the French Institute, on the danaid of Mr. d'Ectot, it was shown that 
the work done amounted to seventy per cent., and sometimes to nearly 
seventy-five per cent., of the power due to the hydraulic head. Yet 
here it is evident that, but for the rotary motion given to the water, 
and the consequent resistance opposed to the head by centrifugal force, 
the performance would be trivial. The friction of the inflowing water 
on the smooth cylindrical surfaces of metal (the machine was made of 
tin) would furnish but an insignificant propelling power. Moreover, 
the partitions in the circular space between the bottoms are entirely 
essential to the performance of the machine. 

The Thompson turbine, therefore, is liable to no theoretic objection 
upon the score that it receives the water by the circumference to dis- 
charge it by the centre. It is only important that the cylindrical section 
of the interior of the wheel should be enlarged relatively to that of the 
circumference, to correspond to the diminution of radial velocity which 
takes place toward the openings for discharge. 

g-irard's hydraulic pivot. 

Before leaving the subject of turbines, one very important and ingen- 
ious invention of Mr. Girard, tending greatly to reduce the wear and 
tear upon a point which is especially liable to suffer, while its failure is 
a misfortune of the most serious gravity, must not be overlooked. The 
pivot on which the axis of the wheel rests bears the whole weight of the 
wheel and shaft, and to some extent that of the escaping water. From 
the very rapid rotation there is great liability to wear away by friction. 
Mr. Girard's invention is one by which this friction is made almost wholly 
to disappear, an effect which is produced by what lie calls his hydraulic 
pivot. The principle of this contrivance will be understood by compar- 



GIRARD'S HYDRAULIC PIVOT AERIAL MOTORS. 119 

ing it to the piece of apparatus commonly called the hydraulic bellows, 
used to illustrate the hydrostatic paradox. Or it may be compared to 
an ordinary hydrostatic press, in which a very small force may coun- 
terbalance a great one. 

To the bottom of the revolving shaft is firmly attached a horizontal 
circular plate of iron. To the support of the socket in which the shaft 
is pivoted is fixed another similar and equal plate. The two meet on 
their entire circumferences, and their surfaces are made so truly plane 
as to form a water-tight joint. But at a little distance within the cir- 
cumferences, toward the centre, these plates have an annular cavity, or 
broad groove, cut into them in the lathe, which, when they are in contact, 
forms a perfectly closed chamber. It suffices that one only of them 
should be thus indented. A small perforation through the lower or 
fixed plate is connected with a tube which is carried upward to the 
hydraulic head, and is put into communication with the water of the 
source. The water descending the tube enters the annular chamber 
just described, and exerts an upward pressure proportioned to the area 
of the ring and the height of the head. The weight of the turbine, 
axis, &c, being known, it can easily be calculated what should be the 
size of the ring that the weight may be just balanced. The friction on 
the pivot will thus be reduced as nearly as possible to zero. If the 
hydraulic pressure slightly exceeds the weight it will be all the better, 
for, in that case, the opposed bearing surfaces will have a film of fluid 
interposed between them, which will prevent wear altogether. The 
amount of water escaping through so minute a fissure will at the same 
time be so small as to be quite inappreciable. 

YI._AEE1AL MOTOES. 

The atmosphere presents a source of motive power which, but for its 
large and capricious fluctuations, would be made much more generally 
subservient than it is in fact to the uses of the industrial arts. Though 
not suitable for impelling heavy machinery, its presence everywhere, 
which is always a recommendation, makes it in certain circumstances 
an invaluable auxiliary to the minor and especially to rural industries. 
There are many territories where water powers do not exist, and where 
motors driven by artificial heat are not economical except for large man- 
ufactures. In such situations the wind performs a service of inappreci- 
able value in superseding the labor of men or animals. It is an objection 
to the windmill that it is often idle when its service is most wanted. For 
rural industries it will generally be practicable so to arrange work as to 
take advantage of the favorable seasons without being too much incom- 
moded by the calms ; but in case a motive power is required to be at all 
times available, the object may be secured by means of a windmill hav- 
ing, while in action under favorable circumstances, an excess of power, 
which may be used to accumulate a head of water for use in the inter- 
mediate intervals. 



120 PARIS UNIVERSAL EXPOSITION. 

The practical problem of applying to use the motive power of the 
wind is complicated by the frequently changing direction of the wind 
itself. In most windmills the difficulty is met by making the part of the 
machinery which constitutes the motor proper rotatory around a verti- 
cal axis. This construction involves necessarily a weak point, and affords 
opportunity for the exercise of ingenuity in devising means for securing 
sufficient strength without greatly adding to the weight or increasing 
the friction of the moving parts. The two objects are to a certain extent 
incompatible 5 and it is probable that in general it is only the considera- 
tion of cheapness which determines the adoption of a form which had 
its origin in the infancy of mechanics. 

There were exhibited in the Exposition four windmills in actual oper- 
ation, and one in design. Of the four, three were French, and one was 
Belgian. The number of sails was different in the different machines, 
one having as many as twenty, the others sixteen, eight and six. The 
peculiarities of construction which deserve attention are those which 
concern the regulation of velocity under varying force of wind. 

]\iAHorc>ou's windmill. 
In the windmill of Mr. Mahoudou, of St. Epain, France, the sails, 
which were of canvas and six in number, were attached at the outer 
extremity of the arm to a yard possessing a certain degree of flexibility, 
but stiff enough to resist the ordinary pressure of the atmosphere, and 
to maintain the sail at a determinate angle of inclination. Under a 
higher degree of pressure, the springs, by yielding, reduce the amount 
of surface exposed to the wind, in proportion to the excess of pressure ; 
and thus serve to maintain a tolerably uniform rate of rotation. 

EOR3IIS\S WINDMILL. 

A different contrivance for the same purpose was observed in the 
wiDcliniLL exhibited by Mr. Formis, of Montpellier. In this machine the 
sails, which are of canvas, as in the one just described, are attached on 
one side to rigid arms; while they are stretched by yards attached by 
one end to the arms, at points about half way from the centre, and by 
the other to the free angles of the sails. From each of these free angles 
a cord is carried to the top of the next following arm. and thence, pass- 
ing over a pulley, is continued down the arm to the axis of rotation, and 
through this axis, (which is hollow,) length Arise, to the opposite extrem- 
ity, where the whole system of cords is uuired. and by means of a suita- 
ble joint and lever is connected with a weight which acts as a governor. 
It is evident that when the pressure of the wind is sufficient to over- 
come the counterpoise, the sails will become more inclined, and will pre- 
sent a smaller extent of surface to the wind. The windmill of Mr. 
Formis was provided with eight sails. 

THIRION'S WINDMILL. 

A more important and more interesting machine of this class was pre- 



AERIAL MOTORS — THIRIONS WINDMILL 



121 



sen ted, however, from Belgium, by Mr. Tkirion. In this the sails are 
of wood and are from twelve to twenty in number. Each sail is hinged at 
two fixed points, one at the foot of the sail and at the axis of rotation, 
and the other at about half its length, where it is attached to a fixed 
circle, forming part of a framework by means of which the force is to be 
transmitted. Another circle, of the same size as this, and movable in 
guides, is attached to the centre of each sail through the medium of con- 
necting rods. This circle, by its movement, affects simultaneously the 
inclination of all the sails. It may be set, in the beginning, at any incli- 
nation at pleasure ; after which there can be, during the action of the 
machine, no diminution of the inclination ; but in case the wind becomes 
violent the inclination will be increased by the effect of a centrifugal 
force governor acting on the movable circle. 

While this contrivance has its merit, the most important and ingen- 
ious peculiarity of Mr. Thirion's windmill consists in a mode, which is 
certainly entirely original, of transmitting rotary motion between shafts 
which are not in the same direction, or in parallel directions, without 
the use of bevel gearing. It was not employed in the mill exhibited, 
but has been in use for a number of years in othei mills by the same 
constructor. This ingenious Fig. 35. Fig. 36. 

invention is shown in the , | 

Figs. 35 and 36 annexed. It ! | 

is a spiral formed of a plane 
iron, or, rather, steel band, 
which is attached at its op- 
posite ends to the two shafts 
to be connected. The diam- 
eter of the spiral will neces- 
sarily, in order to secure 
sufficient strength, be con- 
siderably larger than that of 
the shaft; and the attach- 
ment may be made by means of a cast-iron cap, having on one side a 
socket for the shaft and on the other a flat surface to receive the spiral. 
The breadth of the iron band or ribbon which forms the spiral is about an 
inch and a half, and its thickness a little more than a quarter of an inch. 
The total diameter of the spi- „. M „. ■• 

ral is about one foot. For a 
joint of transmission forming 
a right angle, about fifteen 
turns of the spiral will suffice. 
The entire spiral may be made 
of a single ribbon, or it may be made up, as it has been in some cases, 
of a number of parts connected together, as shown in Fig. 37, by tongue 
and groove. Experience has proved that this mode of transmission 
performs perfectly, without being liable to get out of order or to give 






122 PARIS UNIVERSAL EXPOSITION. 

way. Its strength is very considerable, but cannot be indefinitely 
increased, since a thickness exceeding that which is adopted would 
bring too great a cross-strain on the metal. A number of these joints 
have been in operation without accident for several years. The mode 
of securing the spiral at its extremity is shown in Fig. 38. After 
the end has been riveted to the plate, a cross-bar is fastened below 
the rivets, so as to prevent a flexure at the point weakened by drilling. 
The windmill of Mr. Thirion, though self-adjusting to the wind, is not- 
provided with the ordinary wind- vane. In fact, the sails themselves ful- 
fil the usual function of the vane, only that they are no longer, as in 
the ordinary construction, presented to the wind on the side of the tower 
from which the blast comes ; but swing round, so to say, behind the 
tower. This part of the structure is therefore merely an open framework. 
The weight of the sails is balanced by a heavy counterpoise, and the 
whole rotating structure rests on balls, on a circular railway, resembling 
in this respect the dome of an astronomical observatory. 

MOERATH'S WTXD3ITLL. 

The particular windmill which seems, however, to be the most decided 
improvement upon past forms of this motor, isthatwhich was exhibited in 
designs by Mr. Moerath, of Vienna, which may be called an aerial turbine. 
This is shown in Plate V, Figs. 1, 2, 3, and 4, in which Fig. 2 is an eleva- 
tion, showing the interior of a circular structure designed to enclose the 
wheel carrying the sails. The rotation is horizontal, the wheel turning 
round a central axis, shown at L. The form of the wings is exhibited in 
Fig. 4, which also shows in plan a series of fixed directrices, a b, a' b'. by 
which the currents of the air, coming in the direction indicated by the 
arrow, are deflected upon the sails of the windmill. This machine, there- 
fore, resembles the turbine of Mr. Thompson, exhibited by Williamson 
& Co., the air entering by the circumference and escaping by the centre. 

The sails are made of canvas, but their form is determined by the 
iron arms or frames to which they are attached. These frames are 
secured at top and bottom to two circular plates, which are fixed to the 
axis. Beneath the whole there is also attached to the axis a pulley 
which, by means of guide rollers, represented at K, (Figs. 2 and 3.) 
maintains it in position. The weight is sustained, and the level more 
truly preserved, by means of the rollers S, Fig. 3, themselves resting 
by their axes upon the smaller friction-rollers s s'. The guiding Avheels 
K are sustained by brackets from the frame, shown at G- in both figures. 
The power is applied through conical gearing, as shown at m or n. or in 
any other way. 

The structure on which the motor rests may be of wood, brick or 
stone ; but the chamber in which the wheel is placed is designed to be 
constructed of iron, except the roof. Its base H forms a cast iron 
crown, to which are bolted the brackets G. and from which rise verti- 
cally, at regular intervals, a series of rolled iron plates, which form the 



AERIAL MOTORS MOERATH 7 S WINDMILL. 123 

directrices for the wind and also the support for the superstructure. It 
will be seen, by comparing the positions of the directrices in the plan 
with the directions of the arrows, that on the side on which the wind 
and wheel move in harmony, the wind can enter until its direction 
becomes tangential to the structure ; while on the other side it is cut off 
from entering at all, by the overlapping of the borders of the direc- 
trices, up to the point where it becomes capable of such a deflection as 
to favor rotation. This wheel will, therefore, turn equally well, from 
whatever quarter the wind may blow. 

The provision made for guarding against excessive velocity of move- 
ment in the case of high winds is iDgenious. To every one of the 
directrices there is attached, on the outside, a shutter, wide enough to 
close entirely one of the openings, but pivoted by the middle points of 
its extremities, so that instead of closing one opening entirely, it closes 
the adjacent halves of the two between which it is placed. Thus, when 
all the shutters are closed, they meet each other half-way like the blinds 
of windows. In the plan, PI. V, Fig. 4, these shutters are seen at d c, d / &. 
In calm or in light winds they stand in the positions in which the figure 
represents them. But when the velocity of movement begins to rise 
above what is designed to be the limit, they are closed to a greater or 
less extent, by the effect of a self-acting apparatus represented in Fig. 
2, and on an enlarged scale in Fig. 1, and through a system of connect- 
ing rods shown in Fig. 3. The main axis of rotation D carries a gear 
wheel r, which acts on the governor, Fig. 1, through the smaller wheel 
r', secured to the vertical axis of the governor. By the divergence of 
the arms of the governor the doubly conical friction wheel y is raised, 
and is brought at length to the point where its upper conical surface is 
in contact with the conical wheels Z and z. The wheel Z is fixed to its 
shaft and operates the conical gear wheels t. The wheel z is idle, its use 
being merely to equilibrate the pressure. The vertical conical wheel t 
turns the tangent screw/ which rests on the perimeter of a large wheel, 
seen dotted in the plan of this part of the machine, Fig. 3. To this wheel 
x are attached a number of rods £, equal to the number of shutters ; and 
these rods, by their opposite extremities, are fastened by hinge-joints to 
the outer extremities of the shutters, severally. An examination of the 
plan will show that if the wheel x be turned from right to left, the shut- 
ters will be drawn inward ; and if the movement be sufficiently con- 
tinued, they will be closed entirely. The action of the wheel Z upon 
the wheel x through the tangent screw, turns it from right to left ; and 
thus by the automatic action of the machine itself the shatters are par- 
tially closed and the impelling force diminished. The velocity diminish- 
ing, the friction wheel y will descend, and Z will cease to act. If, in 
consequence of the reduction of the driving force, the retardation is in 
excess, the friction wheel y will descend until it comes into contact with 
Z' and £ y , of which the first is now idle, and the second turns the bevel 
wheels V, reversing the motion of the gear wheel x, and to a greater or 



124 PARIS UNIVERSAL EXPOSITION. 

less extent re-opening the air passages. There may thus take place a 
succession of oscillations of the bevel wheel y, diminishing in extent if 
the breeze remains steady, until a permanent adjustment is attained. 
But if the wind varies, whether "by an increase or a diminution of its 
mean velocity, the bevel wheel y will act anew and effect a new adjust- 
ment corresponding to the changed velocity. It is not to be understood 
that the wheel x Avill be acted upon in response to every momentary lull 
or gust, since the bevel wheel y has a sufficient freedom of movement 
between Zand Z' to accommodate itself to these, so long as the average 
strength of the wind remains unchanged. But if there is a permanent 
increase or diminution of the wind force, the necessary correction will 
be made with infallible certainty. 

The governor can be thrown out of gear with the machine : and if it 
is desired to leave the mill at rest, the wheel x, after detaching the 
governor, may be turned by hand so as to close the shutters entirely. 

It is a great recommendation in favor of this motor, that it has no 
such weak point about it as has been mentioned as limiting the useful- 
ness or impairing the strength of all the windmills in which the entire 
superstructure rotates around a vertical axis in order to present the 
sails to the wind. The present machine may possess all the strength of 
framework which it is possible to give to a turbine or water wheel. 

It is also another and an important recommendation in its favor, that 
it is not liable to damage by the most violent storms : since, as we have 
seen, the effect of an increased strength of wind is to cause the shutters 
to close in proportion to the degree of the increase, so that when the 
violence is excessive they close almost altogether. Observations have 
been made of the action of mills of this construction which have been 
long in use; and the result is that the rotation is steady, and only 
slightly variable in rapidity, no matter how great may be the fluctua- 
tions of the wind. In the midst of the most furious gales, the work goes 
uniformly on. the wheel maintaining permanently the same mean velocity 
to which it was limited in the original adjustment of the governor. 

There are large portions of our country in which the windmill is almost 
unknown. There are other portions, as in California, where they are 
extensively used and where objects of this class frequently strike the 
attention of the traveller. They would be undoubtedly much more 
generally introduced, if. in their ordinary forms, they were less rude 
and more efficient. They adapt themselves admirably to the circum- 
stances of sparse settlements, in prairie districts and low alluvial regions, 
where streams are few and sluggish, where fuel is costly, and where the 
population, chiefly engaged in the cultivation of the soil, and living in com- 
parative isolation from each other, hud the conversion of their grains 
into flour and meal for domestic uses a serious tax upon both their time 
and their means. To such, the mills of Mr. Moerath, which are said not 
to be expensive, (the cost was not given,) would be extremely serviceable : 
while for many other light industries, such as the grinding of paints and 



ELECTRO-MAGNETIC ENGINES. 125 

drugs, or the elevation of water for irrigation, for drainage, or for the 
ordinary uses of life, they are perfectly well adapted, and are probably 
in point of economy as cheap as any description of motor which could 
be provided for the same work. 

VII.— ELECTKO-MAGKETIC ENGINES. 

Several machines operated by the power of electro-magnetism made 
their appearance in the Exposition. Without counting the considerable 
number designed for purposes of demonstration, or intended only to 
serve as philosophic toys, there were present a number which had been 
constructed with a serious industrial object. It has been long since 
generally considered as settled, that motive power can only be obtained 
by means of electro-magnetic combinations at an expense which forbids 
the employment of such a power upon a large scale ; but for many minor 
purposes in which the consideration of cost is unimportant, the con- 
venience of application of this power has secured for it an acceptance 
which is becoming every year more general. The extensive introduction 
into families of the sewing machine has created a special demand for 
small powers; and it is here that the electro-magnetic engine finds a 
field of usefulness to which it is peculiarly adapted. 



One of the machines presented in the Exposition, the invention of 
Mr. J. H. Oazal, of Paris, is expressly designed for this purpose, and has 
received from the jury the distinction of an honorable mention. 

This is exceedingly compact, and as it takes the place and has the 
appearance of the fly-wheel of the common machine, it adds nothing to 
the weight or to the seeming complication. It is formed of a thick disk 
of soft iron, cut into the shape of a gear-wheel ; a deep groove being after- 
wards cut down in the middle of the circumference, which is wound 
with insulated wire. The ends of the wire are soldered to insulated 
thimbles, which, by means of tangent-springs, introduce the battery 
current in the usual way. Surrounding this magnetic wheel is a heavy 
iron ring insulated on its interior surface in a manner to present eleva- 
tions corresponding to the teeth or salient points of the wheel. This 
ring is fixed and the whole apparatus is more or less concealed by a neat 
annular metallic envelope. When the teeth of the wheel pass before 
the prominent parts of the surrounding ring, there is a near approach to 
contact, and the attraction is strong. When these teeth are half-way 
between those points, the opposite attractions are balanced. At the 
moment of nearest approach the current is arrested ; it is renewed again 
at the intermediate position. In the interval, while the current is not 
flowing, the magnetic wheel maintains the motion in the manner of a 
fly-wheel. 



126 PARIS UNIVERSAL EXPOSITION. 

BIRMINGHAM COMPANY'S ELECTRO-MAGNETIC ENGINE. 

Ad other motor of this class is exposed in the British section by the 
Electro-Magnetic Company of Birmingham. In none of the electro- 
magnetic machines produced of late years does there seem to be much 
of originality. In fact there does not appear to be room for much. The 
efforts of inventors are bounded, and must be so, to the endeavor, by 
varying the combinations of the parts, to secure the largest amount of 
motion with the smallest differences of distance between the attracting 
or repelling poles. 

The engine of the Birmingham company has four sets of fixed electro- 
magnets of the U or horse-shoe form, two sets at each end of an oscillat- 
ing beam by which the power is to be utilized. The magnets of each set 
are arranged in two tiers, one above the other. The armatures of these 
several magnets are carried by rods depending from the ends of the 
beam; but the rods pass freely through these armatures without being- 
fastened to them. When, therefore, an armature, in the descent of the 
rod, comes into contact with the magnet to which it belongs, the rod 
continues its motion and leaves the armature resting there. In the 
return motion the rod lifts the armature again, by means of a collar or 
enlargement which has been given to it at the place intended. Each 
armature has thus its collar, and these several collars have been so fixed 
upon the suspended rods, that the armatures reach the faces of their 
respective magnets successively, and no two at the same time. 

In the action of the machine, the battery current actuates the magnets 
on the side of the descent ; while on the other side the current is cut off. 
The machine acts therefore only by attraction. The armatures are of 
soft iron. As these armatures approach their magnets successively, it 
will happen that whenever one becomes inefficient, by coming into con- 
tact with its magnet, the next will be in position to exert a very high 
attractive force. And this force increases until this next makes contact 
with its magnet in like manner. On the whole it may be said of this 
machine that it presents what may be called a judicious arrangement of 
parts, but contains nothing Avhich is new and nothing which can prop- 
erly be called ingenious. 

KRAVOGL'S ELECTRO-MAGNETIC ENGINE. 

In the Austrian section appeared an electro-motor by Kravogl. which 
by its compactness, and by the great energy which it seemed to manifest 
within small space, excited much interest, but the construction was 
totally, and it might be said ingeniously, concealed: and neither the 
exhibitor nor any representative of his was present to give any informa- 
tion in regard to it. On attaching the battery it was instantly set in 



kravogl's electro-magnetic engine. 127 

motion, but this fact was the only evidence presented of the character 
of the machine, since no electromagnet was visible. 1 

1 Since this report was written, the following description of the machine above mentioned 
has appeared in a report on the electro-dynamic apparatus of the Exposition, made by 
Robert Sabine, Esq., of the British Commission : 

"A new construction of electro-motor is shown by M. Kravogl, of Innsbruck, in which 
a hollow heavy wrought-iron wheel is rotated by means of a permanent magnet creeping up 
inside it. In principle the apparatus resembles exactly a tread-mill. Inside the outer case 
of iron in the centre of the section is a circular tube of brass, and in the annular space 
between the two tubes three coils of insulated wire are wound at right angles to the tangents 
of the periphery and connected with contacts properly placed at the axis. Inside the interior 
brass tube or ring is a magnet carried on anti-friction wheels, and occupying, perhaps, one-third 
of the whole circle. When a current is sent through the wire surrounding the magnet, the 
latter is deflected, or creeps up the ring on one side or the other according to the direction of 
the current, and by doing so displaces the centre of gravity of the whole system towards 
that side. In consequence the wheel must turn slightly on its axis to compensate this dis- 
placement. But while it does so the magnet creeps up still further, so that the wheel acquires 
a continuous rotatory motion. There is very little friction in this machine, and it is proba- 
bly one of those in which the equivalent of mechanical force, gained by an expenditure of 
an unit of current, would be found the highest. This is not saying much, however, for in 
the best constructed machine this found value must fall far short of the theoretical equiva- 
lent." 

From this statement it appears that whatever may be the coefficient of effective force in 
Mr. Kravogl's machine, the absolute amount of work which it is capable of performing must 
always be extremely limited ; since at maximum it cannot exceed the weight of the magnet 
lifted through a space equal to that described by a point in the periphery of the wheel taken 
at the mean distance of the magnet from the centre of motion. In the machine exhibited, 
the magnet, though of course concealed from observation, could not, from the visible dimen- 
sions of the apparatus, have exceeded a pound or two in weight. To construct a machine 
on this principle, of any considerable power, it would be necessary very greatly to enlarge 
these dimensions. 



CHAPTER III. 

TRANSMISSION OF FORCE. 

Importance of the problem — Loss usually incurred in transmission— Exam- 
ple of Huelgoat— At Niagara — Hirn's telodynamic carle— Difficulties 
encountered by the inventor— how extensively introduced— percentage 
of power delivered— Comparison with common modes of transmission — 
Calles's hydro-aerodynamic wheel— In what respect original— Mechani- 
cal principle involved— Inventor's estimate of economy— Transmission of 
force by means of air highly compressed — experuments at cascia on 
resistance of tubes to flow of air — laws deduced— absolute and rela- 
TIVE resistances— Increase of power without increase of resistance. 

GENERAL OBSERVATIONS. 

Next in importance to the creation of a new motive power may be 
placed any material improvement in the methods of making available 
the powers which we have. Nature often furnishes us with such powers 
in abundance in situations where they cannot be conveniently converted 
to use. The positions of waterfalls are determined by geographical acci- 
dents. These do not always conspire with the causes which promote the 
growth of towns and the development of industries. If it were possible 
to transfer the immense forces which are thus unprofitably expending 
themselves to points where there are hands to direct them, and material 
on which to employ them, they might be made productive of incalculable 
wealth, which is now lost, and of immeasurable benefit to mankind, which 
fails at present to be realized. 

It is even the case not only with natural but with artificial motors that 
it is sometimes convenient, and sometimes, indeed, necessary, to apply 
the power which they furnish at a distance from the source. The exca- 
vation of the tunnel under the Alps furnishes just now an example of 
this description. The drainage of mines and the raising of minerals from 
their depths furnishes another. In Russia, in the year 1861, the great 
government manufactory of gunpowder at Okhta was destroyed by a 
frightful explosion. In the reconstruction of the works it was determined 
by the minister of war, on the suggestion of General ConstantiuorY. to 
erect the several buildings at such a distance from each other that the 
explosion of one of them should not involve, as happens usually in such 
cases, the ruin of all the rest. This new manufactory, which has gone 
into operation during the present year, 1 is composed of thirty-four differ- 
ent workshops or laboratories, to which motive power is transmitted from 
three turbines, of a total force equal to two hundred and seventy-four 

1 The delay in the publication of this report makes it necessary to remark that the state- 
ment in the text relates to the year J 867. 



TRANSMISSION OF FORCE. 129 

horse-power, along a line nearly a mile in length. Considerations of 
safety may in like manner often make it desirable to separate by a con- 
siderable interval an operation of ordinary industry from the prime 
mover on which it depends. 

Hitherto, in most cases in which such a transmission of power to a 
distance has been attempted by mechanical means, the losses necessarily 
incurred have been enormous. Indeed, beyond a certain quite moderate 
distance, the fraction of the whole force available at the point of appli- 
cation becomes too small to compensate the expense and trouble of the 
operation, and the undertaking is left unattempted. In the great water- 
engine at Huelgoat, of which mention has already been made, the trans- 
mission of the power is as direct as possible, and is reduced to the last 
degree of simplicity, and yet so cumbrous are the connections that a force 
of fifty horse-power is consumed in merely giving motion to the machine 
without any load. A similar example, but on a comparatively small 
scale, may be seen at Magara Falls, near the suspension bridge. In this 
place there is a gorge through which the Avaters of the river are forced 
with an abundance of wasted power sufficient to turn all the machinery in 
the world. But this power is expending itself between two precipitous 
cliffs three hundred feet deep. No fraction of it can be turned to use with- 
out being first lifted perpendicularly upward through this great interval. 
For the most part, therefore, it has been allowed to run to waste. 

An attempt has been made, nevertheless, to draw from it the insig- 
nificant amount of power necessary to drive a saw-mill on the brink of 
the precipice, and for this purpose a waterwheel has been established at 
the river's edge, and connected with the saw-mill by means of several 
long iron rods. These rods are jointed that they may follow the irregu- 
larities of the face of the precipice, and receive the support and guidance 
of stays attached to the rock. The object to be accomplished in this case 
is small, and the power is abundant, so that a little more or less of waste 
is a matter of no consequence ; but this renders the example more striking, 
since the power required to move the apparatus of transmission cannot 
be less than that which is needed to drive the mill. 

The great charge upon the prime mover which these cumbrous modes 
of transmission entail restricts within narrow bounds the extent to which 
they can be employed. A discovery which shall greatly enlarge these 
limits cannot but prove to be an inestimable benefit to the world. By 
bringing into use, and employing to give activity to industry, forces 
which must otherwise be wholly and permanently unavailable, such an 
invention is practically a creation of force. 

hirn's telodynamic cable. 

An invention of this kind is presented in the present Exposition, 

originating with Mr. C. F. Hirn, of Logelbach, on the Rhine: It rests 

upon a very simple principle, the substitution of velocity of motion 

for mass of matter moved. No truth is more familiar than that a given 

9 I A 



130 PARIS UNIVERSAL EXPOSITION. 

force may be equally represented by a heavy body moving slowly, or a 
light one moving rapidly. With a smart blow from a light hammer we 
may easily crush a pebble, while a gentle blow from a very heavy one 
may produce no effect. In the machine called the wheel and axle a small 
weight acting on the wheel may raise a large one suspended from the 
axle through a given space in a given time ; but a still smaller one at the 
wheel will do the same work, provided the size of the wheel be sufficiently 
enlarged and the velocity of its circumference correspondingly increased. 

In the attempts which have hitherto been made to transmit power to 
distances, it has been the ordinary working velocity of the prime mover 
which has been transferred from the source to the point of application. 
In this form we have seen that force is not advantageously transmissible. 
It was a simple idea, but one truly ingenious, and fertile of admirable 
results, to transform this power into a shape in which, while it should 
not be directly applicable to the uses for which it is required, it should, 
nevertheless, possess the property which it did not possess before, of 
transportability. 

It is this transformation which is the essential part of Mr. Hirn's inven- 
tion. The motor is made to give a high velocity to a pulley wheel, and 
this wheel is employed to carry a cable which passes over another pulley 
at the point where the power is to be applied to use. The cable may be 
light in proportion as the velocity with which it travels is greater. 
Theoretically there is no limit to the extent to which this transformation 
may be carried. A hair or a spider web, if it move fast enough, may 
convey the force of a thousand horses. Grant that the velocity may be 
made equal to that of light, and a quantity of matter in the cable wholly 
inappreciable to the senses will suffice for the same purpose. But 
there is a practical limit to the velocity with which a pulley can be run, 
and the cable must have strength to overcome the inertia of the pulleys 
and the passive resistances of friction on the pivots and of the air. 
Happily the object in view may be sufficiently attained without tran- 
scending the limits here indicated. 

The invention thus described, when first presented to the mind, seems 
easy enough of application. Great difficulties were, nevertheless, encoun- 
tered by the inventor in reducing it to practice. The cable, though light, 
requires, when the distance is considerable, to be supported at inter- 
mediate points. For this purpose smaller pulleys are introduced at 
intervals of about one hundred and fifty metres. The cable itself is 
of wire, about one centimetre in diameter, the extreme pulleys four 
metres, and the intermediate ones half as large. The great pulleys 
are driven with a velocity of from one hundred to one hundred and 
fifty revolutions per minute, or from fifty to seventy-five miles an 
hour at their circumferences. The smaller must, of course, make twice 
as many revolutions. In the earlier experiments the wear of the mate- 
rial was found with this rapidity of motion to be enormous. Continual 
failure was the consequence. One after another different kinds of wood 



hirn's telodynamic cable. 131 

and different metals were successively tried in the construction of the 
pulleys. But though their surfaces were made as smooth as possible 
they rapidly destroyed the cable. They were then covered with leather, 
with India-rubber, and with other yielding materials, but the cable 
destroyed these coatings still more rapidly. The substance which was 
found at last to answer the purpose, and to present a surface, which, 
without being worn itself, should not wear the cable, was gutta-percha. 
This is driven compactly into a groove enlarged at the bottom in order 
to secure it firmly to the wheel, and it has been found so durable that, 
after a period of seven years use, it still remains sensibly unaltered. 
The series of experiments which resulted finally in this success extended 
from 1852 to 1860. Id estimating the credit due to the inventor, this 
perseverance, under discouragements so numerous and protracted, will 
not be regarded as the least of his merits. 

Plate IV will serve to render the general description above given of 
the telodynamic cable more clear. In Fig. 1 the position of the prime 
mover is at the extreme left, and that of the receiving station at the 
right. In this view there are presented two intermediate pairs of pulley 
supports. Fig. 2 shows the transmission over an eminence intervening 
between the source of power and the point of application. 

The receiving pulley must run, of course, with the same velocity as the 
transmitting pulley, and as this last has attained its excessive speed of 
rotation by means of a train of accelerating wheels, connected by bands 
or gear work, so at the point of application the velocity must be reduced 
again by a corresponding train retarding. 

In Fig. 4 a, and Fig. 4 b, are shown upon a larger scale the arrange- 
ments of the pulleys of the intermediate or supporting stations. The 
wheels are made as light as is consistent with strength, not only for the 
sake of reducing the inertia of the moving mass and the friction on the 
axes to a minimum, but for the more important object of diminishing 
the resistance of the air. It can hardly be doubted that an abandon- 
ment of spokes entirely, and making the pulley a plane disk, would 
improve essentially the performance, could disks be made at once strong 
enough to fulfil the required function and light enough not materially 
to increase the friction. It will be seen further on that the resistance of 
the air, which Mr. Hirn admits to be equal to the sum of the other 
resistances, is in fact more than double all the rest put together. 

In Fig. 3 is represented the form of the groove into which the arma- 
ture of gutta-percha is compacted, the figure being a cross- section of the 
periphery of the wheel. The dovetail enlargement of this groove at the 
base is necessary, not merely to secure the gutta-percha against dis 
placement by ordinary causes, but to prevent its being detached by cen- 
trifugal force. Mr. Hirn assumes thirty metres per second (98.5 feet) to 
be the velocity which it is expedient ordinarily to give to the circumfer- 
ence of the wheel; but he has carried this occasionally as high as forty 
metres, (131.2 feet). At thirty metres the centrifugal force generated at 



132 PARIS UNIVERSAL EXPOSITION. 

the circumference of the smaller pulleys, of two metres iu diameter, will 
be between ninety and one hundred times the force of gravity; and at 
forty it will be nearly one hundred and seventy times gravity. That is 
to say, as the circumference of such a wheel measures a little over twenty 
feet round, if each foot of this circumference weighs one pound, the 
whole will be dragged in all directions with this last velocity by forces 
which unitedly will amount to nearly a ton and three-quarters. It is on 
this account that Mr. Hirn suggests that the limit of thirty metres had 
better not be overpassed, higher velocities endangering the destruction 
of the wheel. 

The invention of Mr. Hirn was first applied in the transmission of 
moderate powers to moderate distances. Instead of a cable there was 
used in the beginning a band of steel, having a breadth of about two 
and one-half inches, and a thickness of one twenty-fifth of an inch. 
This presented two inconveniences. In the first place, on account of its 
considerable surface, it was liable to be agitated by the winds: and 
secondly, it soon became worn and injured at the points where it was 
riveted. It served, however, very well for eighteen months to transmit 
a twelve-horse power to a distance of eighty metres (266 feet.) A cable 
was then substituted, and this, first introduced in 1852, is still in good 
condition. 

It was in the attempt to extend the system to greater distances that 
the difficulties above spoken of began to be encountered. At the dis- 
tance of eighty metres no intermediate supports were necessary. At 
the distance of two hundred and forty to which the system was next 
extended, such supports were found to be indispensable in order to 
prevent the cable from dragging on the ground. It was only when, 
after the many trials and failures above mentioned, a material had at 
length been discovered which rendered these supports indefinitely 
durable, that this second experiment could finally be pronounced com- 
pletely successful. After this success, however, the extension of the 
system went on rapidly. A single firm, Messrs. Stein & Co.. of Mul- 
house, have applied it in more than four hundred instances with entire 
success. These applications have been made for the most part in France, 
and in the department in which the invention originated, but there are 
some noticeable exceptions. The government manufactory of powder 
at Okhta, in Russia, mentioned above, has introduced it for the trans. 
mission of the force of its turbines over a distance of one thousand 
four hundred metres. Several establishments in Germany employ it 
for distances varying from three hundred and fifty to one thousand two 
hundred metres. An officer of the Danish navy has made one applica- 
tion of it on a line of one thousand metres: and at the mines of Falun, 
in Sweden, a more than one hundred horse-power is transmitted by 
it to a distance of five thousand metres. 

The invariable success of all the applications hitherto made, over 
distances constantly increasing, has satisfied the inventor that power 



hirn's telodynamic cable. 133 

can be economically carried by this method as far as to ten or fifteen 
miles. The experience tlms far acquired has furnished data by which 
the loss attendant on transmission can be very closely calculated. This 
loss, which will of course increase with the distance, may be referred to 
three sources, viz : the friction on the axles of the pulleys, the rigidity 
of the cable, and the resistance of the air. Experimentally it is found 
that, for the two great pulleys at the termini, an allowance must be 
made of two and one-half per cent., and for the intermediate pulleys 
and the rigidity of the cable there must be allowed additionally one per 
cent, for each thousand metres. Thus, for one hundred horse- power 
carried to a distance of ten kilometres, or six miles, the loss will be 
2 J + 10 = 12J-horse power, or one-eighth of the whole $ the resistance 
of the air being still to be added. Mr. Hirn makes allowance for this 
by doubling the last sum; so that one hundred horse-power may, in his 
opinion, with perfect certainty be carried six miles without losing more 
than twenty-five per cent. It will be shown below that this is an under 
estimate. 

The cost of the machinery and its erection is estimated at 5,000 francs 
per kilometre, exclusive of the necessary constructions at the termini, 
which will require an additional expenditure of twenty-five francs per 
horse-power. In the case of one hundred-horse power carried ten kilo- 
metres the total expense will therefore amount to 52,500 francs, or a 
little over $10,000. 

That this mode of transmitting power will soon come into extensive 
use can hardly be doubted. There are parts of our country in which it 
cannot fail to be of immense value. The mineral States in the heart of 
the continent are imperfectly supplied with water-power at the points 
where it is most to be desired. They are still more imperfectly supplied 
with fuel. To them it will be an inappreciable benefit to be able to turn 
to account the force of the mountain-streams which are now running to 
waste, but which, by means of this invention, may not only be made 
available, but made repeatedly available, by damming them at different 
levels. For its practical value, this invention, simple as it arjpears, is 
one of the most important that has presented itself in the Exposition ; and 
the jury have shown that they so regard it, by awarding to the inventor 
the distinction of a grand prize. 

Mr. Hirn has presented some calculations designed to illustrate the 
economical advantages which the telodyriamic cable possesses over a 
rigid shaft or arbor as a means of transmitting force. He proposes, for 
instance, the problem, what weight of arbor and what power of prime 
mover would be necessary in order to deliver a force of one hundred 
horse-power at a distance of twenty kilometres, say two and a half 
miles. In the solution of this question he has considered the weight of 
the arbor and the force which would be necessarily consumed in over- 
coming the friction of its supports; and he concludes at last that the 
horse-power required in the prime mover would amount to the enormous 
total of 788,400. 



134 



PARIS UNIVERSAL EXPOSITION. 



On the other hand, supposing that the prime mover is of the force 
of two hundred horse-power, and that it is required to know what is the 
extreme distance at which this motor can deliver a force of one hundred, 
he linds that this maximum distance would be only 1,545 metres, or 
less than a mile, (a mile being 1,608 metres.) 

The comparison between the two modes of transmission leaves, of 
course, no place at all to the second. But a comparison so presented is 
a tacit assumption that in the practical solution of this important mechan- 
ical problem there is no other choice but between the two modes of trans- 
mission contrasted. Whether or not this assumption is wholly legiti- 
mate we shall presently impure. A different solution of the problem 
is in fact presented in the Exposition itself, and this will now be con- 
sidered. 

CALLES'S HYDRO-AERO-DYNA3IIC WHEEL. 

Another mode of transmitting power to great distances, proposed by 
an exposant from Belgium, Mr. A. Calles, deserves consideration, if not 



Fig. 39. 




Calles's Hydro-Aero-Dynamie Wheel. 



CALLES'S HYDRO-AERO-DYNAMIC WHEEL. 135 

for what it is, at least for what it suggests. The plan of Mr. Calles is to 
make use of air under a certain degree of compression as the vehicle of 
the force to be transmitted, not by accumulating the air thus employed 
in reservoirs, but by driving it, by the operation of the original motor, 
directly into a tube extending to the point of final application, where it 
is to be discharged beneath a wheel submerged in water, which it is to 
turn by its ascensional force. The mode of application is illustrated in 
Fig. 39. 

The idea of employing compressed air as a means of transmitting poAver 
is not new 5 but the mode here suggested of using the power so trans- 
mitted is sufficiently original. The exhibitor claims originality in another 
point of view. His application of the power is not only original in form 
but in principle also. At Mont Cenis, where air is employed as a vehicle 
of force, it is the elasticity of the compressed air which furnishes the 
motive-power. Consequently, it is there important that the compression 
shoidd be carried very far. It is carried, in fact, up to six atmospheres. 
The present apparatus proposes to derive its mechanical advantage not 
from elasticity, but from volume. It is, therefore, here equally important 
that there should be as little compression as is compatible with the attain- 
ment of the object. 

The air being employed to turn a submerged wheel, it will be easily 
understood that the wheel must have the form of an ordinary over- shot 
water-wheel reversed. In the over-shot wheel, it is the weight of water 
which is in the buckets of the descending side, while those of the ascend- 
ing side are empty, which causes the wheel to turn. The motive power 
is the difference between the counteracting weights of the two sides. In 
the submerged wheel driven by air, on the contrary, it is the weight of 
water which is displaced from the buckets of the ascending side, while 
those of the descending side are full, which is the measure of the driving 
power. In the present case, as in the former, this driving power is the 
difference between the weights of the two sides. 

It is assumed by the inventor that air immerged in water ascends to 
the surface with a velocity of one metre per second. In point of fact, 
the rapidity of ascent of air in water will depend very much upon the 
volume ascending, and will be, on an average, materially greater than 
is here stated. But assuming the statement to be correct, it would fur- 
nish a limit to the velocity which can be given to the circumference of 
the wheel ; and a given wheel will perform its maximum of work when 
the supply of air is sufficient to keep its ascending buckets full at half 
this velocity. Considering, however, that the motive power in the case 
is gravity, the most advantageous velocity must be necessarily not 
greatly different from that which experience has shown to be best with 
the ordinary over-shot wheel working in the air — that is to say, must 
not exceed one metre per second at the circumference. 

The compression of the air must evidently be sufficient to overcome 
the pressure of the water at the point of efflux beneath the wheel. This 



136 PARIS UNIVERSAL EXPOSITION. 

point may be taken at three or four metres of depth, and the corre- 
sponding pressure will amount to three or four tenths of an atmosphere. 
As the air ascends, it resumes by degrees the bulk which belonged to 
it before compression. In order to take advantage of this circumstance, 
the velocity of discharge must be so adjusted to that of the wheel that 
the buckets may not be entirely filled at the bottom. Otherwise there 
will be an overflow from the rising buckets, and to that extent a loss of 
motive power. 

The inventor takes no account of the resistance of tubes to the flow of 
air through them. He supposes that at low pressures and low velocities 
this resistance will be insensible, so that the power received from the 
source may be almost wholly re-established by the wheel. He has erected 
a wheel in the park of the Exposition, which is designed to demonstrate 
the truth of this proposition, and to illustrate his system generally. It 
is driven by air compressed by an engine in the palace, and transmitted 
through a tube nine and a half centimetres (3| inches) in diameter, 
and one hundred and fifty-seven metres (more than 500 feet) in length. 
This tube makes in its course fourteen right angles in order to avoid 
the constructions which it encounters on its way. It is computed that 
a force of nine and a half horse-power is expended in compressing the 
air, and that the velocity of efflux is thirty-two metres (more than 100 
feet) per second. On the other hand, the power of the wheel turned 
by the escaping air is stated at nine horse-power. From these figures 
it would result that the loss in the present instance is but about 
five per cent. That there is a fallacy in the calculation is evident from 
the consideration that the loss of a submerged wheel, driven in this way 
by air, cannot be less than that of an ordinary over-shot water wheel of 
the same dimensions ; and that this loss is at least one-fifth, and is often 
more than one-third. And it results from the experiments of the Italian 
engineers at Ooscia, on the resistance of tubes to columns of air driven 
through them, that to maintain such a velocity as is stated to be given 
to the air in this experiment, and to the distance named of one hundred 
and fifty seven metres, there would be required an expenditure of force 
without return, sufficient to produce a compression of nearly an atmo- 
sphere and a half. 

TRANSMISSION OF FORCE BY MEANS OF AIR HIGHLY COMPRESSED. 

But though the particular mode here proposed of employing com- 
pressed air as a means of transmitting force may not seem to recommend 
itself on the score of economy, it does not follow that the other method, 
viz., that in which the compressed air is made to act directly by its elas- 
ticity, may not be more eligible. This question deserves examination, 
because if compressed air in tubes will serve economically as a medium 
of transmitting power, there will be a sensible advantage in employing 
it instead of the telo-dynamic cables of Mr. Hirn. of which the exposure 
for great distances above ground, and the many moving parts, consti- 
tute so many liabilities to derangement or injury. 



TRANSMISSION OF FORCE BY COMPRESSED AIR. 137 

The engineers of the Mont Oenis tunnel have expressed themselves 
strongly in favor of the view that the plan is truly economical, and as their 
experience in the use of this form of applying power has been larger than 
any which has been elsewhere enjoyed, their statements deserve consid- 
eration. At the date of the report on the progress of the work in the 
tunnel during the year 1863, they were engaged at a distance of nearly 
two thousand metres from their reservoirs of condensed air, and were 
driving nine borers with a force of two and a half horse-power each. 
The tube conveying he air to the perforators was two decimetres (nearly 
eight inches) in diameter. The air was under a pressure of six atmo- 
spheres, and its velocity in the tube was nine decimetres (three feet) 
per second. The transmission of the power to this distance, and under 
these conditions, was attended with no sensible loss. The pressure was 
not perceptibly less at the working extremity of the tube when all the 
perforators were in operation, than when the machinery was entirely at 
rest. 

Mention was just made of a series of experiments made at Coscia, in 
1837, by order of the Italian government, on the resistance of tubes 
to the flow of air through them. These experiments were made previ- 
ously to the commencement of the work upon the tunnel, and while the 
feasibility of employing compressed air to furnish the motive power of 
the boring apparatus was considered still questionable. It was the aim 
of the investigation, not merely to ascertain the absolute loss of force 
occurring in the transmission of air through tubes of certain partic- 
ular dimensions, and with certain particular velocities, but to determine, 
if possible, what are the laivs which govern the variations of resistance, 
when the velocities of flow and the diameters of the tubes are varied. 
From the results of the experiments were deduced the three conclusions 
following, viz: 

1. The resistance is directly as the length of the tube. 

2. It is directly as the square of the velocity of flow. 

3. It is inversely as the diameter of the tube. 

A table was formed exhibiting the numerical values of the resistances 
which were actually found to exist under the various conditions intro- 
duced into the experiments, these values being referred to the common 
length of one thousand metres. In the actual working of the machines 
in the tunnel at Bardonneche, where, as just mentioned, no perceptible 
loss of power was experienced at a distance of two thousand metres 
from the reservoirs, the tables would indicate that there should be a real 
loss measured by a diminution of pressure to the extent of six millime- 
tres of the barometric column, one atmosphere of pressure being repre- 
sented by seven hundred and sixty millimetres. That is, for a tube two 
decimetres in diameter and a velocity of one metre per second, the 
tables give a loss of three millimetres of pressure per thousand metres 
of distance. But six millimetres is but the one hundred and twenty- 
seventh part of an atmosphere ; and as the total pressure amounted to 



138 PARIS UNIVERSAL EXPOSITION. 

six atmospheres, the loss, as computed from the tables, would amount 
to only one one hundred and sixty-fifth part of the total power which the 
air was capable of exerting. That this loss was not perceptible at Bar- 
donneche was owiug to the want of delicacy of the manometer, or 
pressure gauge, which had only been constructed with a view to show 
differences of one-tenth of an atmosphere. 

A loss, however, which at low velocities and for moderate distances 
is of insignificant importance, becomes sensible and even serious when 
the velocity is considerable, and when the distance is greatly increased. 
Inasmuch as, according to the second of the laws above cited, the resist- 
ance varies as the square of the velocity, for a velocity of six metres it 
will be multiplied by thirty-six while the power will be increased only 
in the ratio of the volume of air delivered — that is to say, only six 
times. The relative resistance, therefore, or the resistance as represented 
by a fraction of the power, will be as thirty- six to six — that is to say, 
will be increased six times. And in general it maybe stated that while 
the length and diameter of a tube remain unaltered, and while the abso- 
lute resistance which it opposes to the flow of a current of air through 
it varies as the square of the velocity, the relative resistance, or the 
fraction of the power stored up in the current which the resistance con- 
sumes, is only as the simple velocity. 

In the case before us, the increase of the velocity to six metres per 
second, supposing it to take place, woidd increase the absolute resist- 
ance to one hundred and eight millimetres (thirty-six times three) per 
one thousand metres. Experiment finds the value to be one hundred 
and seventeen, which, for the distance supposed of two thousand metres, 
woidd give a total of two hundred and thirty-four. The absolute resist- 
ance would amount then to ff-J =^ nearly of an atmosphere, or -^ of 
six atmospheres; but the relative resistance would be but the sixth 
part of this, or gf^ =j^q of the total power. 

The power of compressed air varies as the product of its pressure and 
its volume ; or when the pressure is constant, as the volume simply. 
But the volume delivered varies as the velocity multiplied by the square 
of the diameter of the tube. As the resistance is inversely as the diam- 
eter and the volume directly as the square of the diameter when the 
velocity is given, it follows that under a given pressure and velocity the 
relative resistance, that is to say the resistance divided by the power, 
will vary inversely as the cube of the diameter. TVe may therefore 
increase the power transmitted, and diminish at the same time the resist- 
ances both absolute and relative, by enlarging the diameter of the tube. 
There is no doubt a practical limit to this expedient, but it would not be 
to transcend this limit to employ a tube of fifty centimetres, or twenty 
inches in diameter. The cross-section of such a tube, as compared with 
the tube of twenty centimetres actually used at Bardonneche. would be 
^-=6J times larger, and it would discharge, with a velocity of one metre. 
more than as much air as the latter with a velocity of six. The resist- 



TRANSMISSION OF FORCE BY COMPRESSED AIR. 139 

ance would also be diminished in proportion to the increase of the diam- 
eter — that is, it would be but two-fifths of three millimetres, or a little 
over one millimetre per thousand metres of distance. This may be con- 
sidered practically null. It would not amount to a sixth of an atmo- 
sphere in one hundred kilometres, or sixty miles of distance. 

In the supposition just made we have provided for an increase of power 
in the ratio of one to six, without any increase of the velocity of the cur- 
rent of air. The same increase might be secured by a smaller enlarge- 
ment of the tube, accompanied by a moderate acceleration of the move- 
ment of the air, and still without a serious increase of resistance. Making 
the diameter of the tube thirty-five centimetres, a velocity of two metres 
would suffice to discharge the required volume of air, and the resistance 
would be eight millimetres per kilometre. With these dimensions and 
with this velocity the loss of pressure would be about one quarter of an 
atmosphere, or one twenty-fourth part of the total pressure, in a dis- 
tance of twenty-five kilometres, or fifteen miles. Or by making the 
diameter only thirty centimetres, the velocity required would be 2.7 
metres, with a resistance of seventeen millimetres per kilometre, which 
would amount to a quarter of an atmosphere in eleven kilometres, or 
six and a half miles. 

In the comparisons made above between the loss of pressure in the 
several cases supposed and the total pressure, account is not taken of 
the fact that the total pressure cannot be effectively employed in work. 
It is only the excess of the pressure of the compressed air over that of 
the atmosphere which can be turned to account. The effective pressure, 
in the present instance, is therefore but five atmospheres. Comparing 
with this the losses as computed above, we shall have : 

For a power transmitted one hundred kilometres by means of com 
pressed air of six atmospheres moving in a tube of fifty centimetres in 
diameter, with a velocity of one metre per second, a loss of one-thirtieth, 
or three per cent, of the whole. 

For a power transmitted twenty-five kilometres, with air of similar 
pressure, in a tube of thirty-five centimetres in diameter, and having a 
velocity of two metres, a loss of one-twentieth, or five per cent, of the 
whole. 

For a power transmitted eleven kilometres, with air of similar press- 
ure, in a tube of thirty centimetres in diameter, and having a velocity 
of two and seven-tenths metres, a loss of one-twentieth also, or five per 
cent. In this case, if the distance be made twenty-five kilometres, the 
loss will be increased to one-ninth, or eleven per cent, of the whole. 

These results are favorable ; and if all the loss of power attendant on 
the use of compressed air as a means of transmitting force to points 
distant from the source were embraced in those arising from the resist- 
ance of tubes, they might be said to be conclusive. How far this is true 
will presently be examined. 

Previously to the commencement of operations at Bardonneche, it 



140 PARIS UNIVERSAL EXPOSITION. 

was confidently predicted by many who doubted the feasibility of the 
plan adopted, that the leakage would be enormous. This cause alone, it 
was affirmed, would render the system abortive. It was maintained 
that the air could not fail to escape through joints the most accurately 
fitted, and possibly even through the pores of the metal. It is a little 
surprising that an apprehension like this last should ever have been ex- 
pressed, in view of the fact that steam, which is considerably more subtile 
than air, is habitually confined under greater pressures than that of six 
atmospheres, without oozing through the walls of the vessels contain- 
ing it. In regard to the possibilities of leakage at joints, the objection 
was more plausible, but experience has fully demonstrated its fallacy, 
^so leak has ever been detected, though the tube has been often tested 
with candle flames throughout its whole length. Xor have the expan- 
sions and contractions attendant on changes of temperature due to the 
successive seasons, affected sensibly the firmness of the junctions. On 
one occasion it became necessary to leave the receivers full of com- 
pressed air for twenty -four successive days. The loss in all that time 
did not exceed the five-thousandth part of the daily supply. 

The engineers of the tunnel are therefore convinced not only that the 
transportation of motive power to great distances by means of com- 
pressed air is practicable, but that under certain circumstances it may 
be largely economical. They give the following hypothetical example 
in illustration. With a view to avoid introducing into their calculation 
any element in regard to which experiment and practice have not fur- 
nished positive data, they assume for the diameter of the tube thirty 
centimetres ; and for the velocity of the air in it, six metres per second. 
Thej suppose then that a water-power is found of sufficient force to 
maintain in this tube a flow of air at this assumed velocity, under a 
compression of from six to twelve atmospheres, as may be desired. 
And they further suppose that this power is to be transported to a dis- 
tance of twenty kilometres, or twelve miles. 

A tube of thirty centimetres in diameter will discharge four hun- 
dred and twenty -four cubic decimetres of air in one second at the 
velocity of six metres. Each cubic decimetre of air under the pressure 
of six atmospheres is assumed by the authors of the report to represent 
a power of work measured by one hundred and ten kilograms raised 
one metre, or, in technical language, one hundred and ten kdogram- 
metres. Hence, the total volume discharged per second will have 
a force of 46,610 kilogram-metres ; which, being converted into horse- 
power, by estimating, as is usual, the horsepower at seventy-five kilo- 
gram-metres per second, will amount to six hundred and twenty- 
two horse-power. From this must be deducted the resistance of the 
tube. 

According to the tables deduced from the experiments at Coscia. the 
resistance of a tube of thirty centimetres diameter to air moving six 
metres per second, is equivalent to an opposing pressure of seventy- 



TRANSMISSION OF FORCE BY COMPRESSED AIR. 141 

eight barometric millimetres per kilometre of distance. Hence, for 
twenty kilometres, it will be l m .50. And 1.56-^-0.76=2.05 atmospheres. 
The air must, therefore, be compressed to eight atmospheres, in order to 
secure its discharge at twenty kilometres of distance with a pressure of 
six atmospheres and a velocity of six metres. In other words, there must 
be a loss of twenty-five per cent, of the original force, and seventy-five 
per cent, will remain available. But suppose that, instead of seventy- 
five, there be but sixty per cent, of the theoretic horse-power realized, 
there will still remain 373 horse-power disposable- for use. 

The cost of the tube laid down and ready for work is estimated at fr. 
800.000=1160,000 ; being $8,000 per kilometre or $13,000 per mile. This 
estimate is probably abundantly large, as the tube would weigh only 
about one hundred tons to the kilometre, or 2,000 tons for the entire 
distance. Two thousand tons, at $50 per ton, would amount to one hun- 
dred thousand dollars ; leaving $60,000, or nearly $5,000 per mile, for 
transportation and laying. 

The interest on the investment would, at six per cent, amount to $9,600 
per annum, which would be equivalent to $25 75 per horse-power per 
annum ; and this for a power working night and day. A steam-engine 
working in like manner constantly, would consume about twenty-one tons 
of coal per horse-power per annum, allowing five pounds per horse-power 
per hour. This is a large allowance, but reducing it to three pounds 
per hour or twelve tons per annum, there would still, with coal at $5 
per ton,, be a large balance in favor of the economy of the power derived 
from the compressed air. 

The authors of the report further estimate that a larger power, say 
one of eight or ten thousand horse-power, carried to a greater distance, 
say fifty kilometres, or thirty miles, would cost pro rata much less ; not 
more perhaps than one-half or one-third the amount above computed. 
Thus it is observed that the cascade of Marmora, on the Avellino, offers 
a minimum theoretic horse-power of 160,000, of which 20,000 at least 
might be conveyed fifty kilometres or more from the source, through the 
medium of compressed air, and a great deal more cheaply than an 
equivalent amount of power could be created by steam at the place 
where it is applied. 

These calculations seem conclusive ; and if it is true that they are in 
all respects correct, and that they embrace all the sources of loss attend- 
ant on this mode of transmitting power, they must be regarded as being 
conclusive in fact. It is to be borne in mind, however, that whenever 
air, or any other elastic fluid, is compressed by force, there is generated 
an amount of heat Avhich is the exact equivalent of the force employed 
in the compression, and which elevates the temperature of the air com- 
pressed. Were this elevated temperature to remain permanent, it would 
be reconverted into force on the subsequent expansion of the air in 
working, and no loss would result. But as the original temperature is 
that of the weather and of all surrounding things, the temperature of 



142 PARIS UNIVERSAL EXPOSITION. 

compression is above the general level, and in the natural tendency of 
heat to equilibrium, it must soon disappear. If the air, after compres- 
sion, were to be imprisoned in a receiver of invariable capacity, the fall 
of temperature would be attended with a corresponding fall of pressure ; 
and as the work which by re-expansion, after compression, air is capable 
of performing, is dependent upon pressure and volume conjointly, there 
cannot but occur here a serious loss. There is actually a loss, by cool- 
ing, of exactly as much power as was employed in the compression ; but 
as the air, in consequence of its change of density, remains still under a 
pressure much superior to that of the atmosphere, it is capable of still 
doing work, and if allowed to expand will do it at the expense of the 
heat which it contains at the natural temperature. In its expansion, its 
own temperature wiU accordingly be depressed, but not by any means 
so much as it was raised during compression. 

The amount of the loss resulting from this circumstance admits of 
being exactly computed. It will vary with the absolute pressure to 
which the air is subjected. To take the case at Bardonneche where a 
pressure of six atmospheres is aimed at and secured, for every hundred 
horse-power employed in compression, sixty horse-power only remain 
available after the heat produced by compression has passed away. In 
this case, the air, instead of being reduced to one-sixth of its volume by 
the force which raises its pressure to six atmospheres, as it would be if 
there were no heat generated, actually begins to enter the reservoir 
when its volume is reduced only in the proportion of 3.6 to one. Its 
density is therefore 3.6 times that of the common air. As the reservoir 
into which it is driven at Bardonneche is not one of invariable capacity, 
but is maintained by a hydraulic head under the constant pressure of 
six atmospheres, its density increases as it cools, and becomes equal to 
6, when at length it has attained the original or normal temperature of 
the weather. But this increase of density is attendant with a corre- 
spondent diminution of volume, while the pressure remains unaltered, so 
that the amount of work it is capable of doing is reduced just in propor- 
tion to the contraction, that is, in the proportion of 6 to 3.6, or one to 
six-tenths. 

If it were designed to employ higher pressures, the loss would be in 
still greater ratio. Thus, should air be forced into a reservoir under a 
hydraulic head equal to eight atmospheres, it would happen that for 
every one hundred horse-power of compressing force expended, there 
would ultimately remain only fifty-live horse-power available for subse- 
quent use. At a compression of eleven atmospheres, (more exactly 
10.815,) the loss would amount to precisely one half. On the other hand. 
at a compression of only four atmospheres there would be secured sixty- 
seven per cent, of the compressing power : at a compression of three 
atmospheres, seventy-three per cent; and at a compression of two. 
eighty-five per cent. 

The engineers of Mont Cenis have taken no account of this very seri- 



TRANSMISSION OF FORCE BY COMPRESSED AIR. 143 

ous source of loss. They do not fail to recognize the fact that a loss 
occurs, but they treat it as unimportant. Their only notice of it is in 
the following paragraph: 

" There is a final consideration to be mentioned in regard to the com- 
pression of air, which, to say the truth, interests rather physical science 
than the practical application of the system of compression. Air, 
when compressed, abandons a part of its latent heat, which becomes 
sensible and diffuses itself among surrounding media. We fail of data 
to enable us to judge of the degree of influence which this fact infallibly 
exercises upon the motive power which operates the compression ; we 
can say, however, on the other hand, that, industrially speaking, it is of 
an importance so small that it may be entirely neglected. At any rate, 
our previsions for estimating the disposable force necessary to produce 
a certain quantity of compressed air having been founded always upon 
experimental data derived from the effects of compression actually per- 
formed, we have thus made allowance for the resistances proceeding 
from this phenomenon, and we can accordingly defer its more accurate 
study, which we reserve for future attention. 

" Meanwhile we cannot but suggest that the fact of the production of 
heat in the compression of air giving place to the inverse phenomenon 
when the air resumes its original volume — this second fact is for us in 
the highest degree advantageous. The air flowing into the extremity of 
the gallery at the tension of six atmospheres, in resuming by dilatation 
the tension of the common air, absorbs from surrounding media the same 
quantity of heat which it had emitted in the act of compression ; and this 
absorption of heat tends to depress the temperature of the gallery, which 
is naturally elevated, and is made more so by the presence of the work- 
men and by the combustion of the lamps and the gas beaks." 

The authors of the report, by deferring to the future the more partic- 
ular study of the influence which the compression of air must have 
upon the economical value of this mode of transmitting force to dis- 
tances, have permitted themselves to fall into a serious error. They 
have failed to detect the fact that the loss is not unimportant ; and they 
have assumed too hastily that the heat taken up by the air in expanding 
is equal in amount to that which it had emitted while undergoing com- 
pression. The difference is very large. To them, and for the purposes 
which they had in view, it was indeed a matter of no practical import- 
ance whether, abstractly considered, the mode was economical or not. 
The force was needed in the tunnel ; compressed air offered the most 
advantageous expedient for introducing it there, and the water power 
required to compress it was withdrawn from no useful purpose, but was 
running to waste. The question whether or not the fraction of this 
wasted power which was turned to account was or was not the largest 
possible, was a question of secondary importance so long as this frac 
tion was adequate to the work to which it was to be applied. It is suffi- 
ciently evident, nevertheless, that the compressing engines established 



144 PARIS UNIVERSAL EXPOSITION. 

at Bardonneche have never produced in practice the quantity of com- 
pressed air which was expected from them. 

The construction of these compressors is very simple. They operate 
by applying the living force of a large column of water descending in an 
inclined tube, to drive a body of confined air into a receiver within which 
there is maintained a constant pressure of six atmospheres by means of 
a hydraulic head. Each compressing engine resembles therefore, sub- 
stantially, a huge inverted siphon, having the long arm inclined and the 
short arm vertical. The cross-section of this siphon is uniform through- 
out, except at a point in the long arm near the bend, where there is intro- 
duced a valve for the purpose of regulating the periods of motion and 
rest of the contained water column. At this point the tube is enlarged 
so as to make the valve opening equal to the full cross- section of the 
tube, and the valve itself, which is a spindle or puppet valve of peculiar 
form, somewhat ovoid in shape, or resembling rather a boy's peg top, 
drops in opening into a chamber, formed by the enlargement of the 
tube, of such dimensions that the annular space allowed for the flow of 
the water around it is still equal to the same cross-section. These pre- 
cautions are taken to prevent the loss of living force by any change in 
the velocity of the moving mass. 

The short arm of the siphon is the chamber into which is introduced 
the air to be compressed. At its upper extremity it communicates by a 
valve with the receiver of compressed air. This valve is kept closed by 
the pressure of the air in the receiver, so long as the pressure beneath it 
is less, but when the air beneath attains by compression the same ten- 
sion as that already in the receiver, the valve opens and the new charge 
enters. 

The compression chamber, or short arm of the siphon, receives its suc- 
cessive charges of air from the atmosphere by valves opening inwards. 
It is freed from water after each pulsation or act of compression, by 
means of other valves, which open at a level somewhat above the bend 
of the siphon, so that the bend itself and the long arm remain always 
full of water. 

The action of the machine will now be easily comprehended. The air 
chamber being full of air at the ordinary density of the atmosphere, the 
great valve in the long arm of the siphon is opened, and the water rushes 
through the bend into the short arm, compressing the air before it. and 
finally driving it into the receiver. The water then comes to rest, the 
large valve of the long arm closes, the discharge valve of the short arm 
opens, the water escapes and a new charge of air enters. 

The difference of level between the head of the driving column of water 
and the point of discharge is twenty- six metres. The diameter of the tube 
is sixty centimetres, and the height of the air chamber, measured from the 
level of discharge at bottom to the valve opening into the recipient at 
top, is four metres. These measurements would give for the total capac- 
ity of the air chamber 1.13 cubic metres; and this is the maximum charge 



TRANSMISSION OF FORCE BY COMPRESSED AIR. 145 

which the machine is capable of compressing at a single impulse. The 
charge actually compressed, however, is less than this, and is determined 
by the condition that the resistance which it opposes to the driving force, 
daring its compression and subsequent passage into the recipient, shall 
exhaust this force exactly, without excess or deficiency. In case the 
resistance is in excess, a portion of the air will fail to pass into the 
receiver and so be lost. In case it is in deficiency a portion of the motive 
power will be uselessly expended, and, moreover, the column of water 
will strike the top of the air chamber with violence, and may damage 
the machine. The practical adjustment of the bulk of the charge to the 
power of the engine is attained by a tentative process, a series of small 
valves being adapted to the side of the air chamber in a vertical row, 
through which the air can escape, but which the water by its inertia 
closes successively as it rises. If, in a series of experiments, these valves 
be secured one after another, beginning at the top, the charge of air will 
be gradually increased, until at length it is found to have the volume 
required. 

There are at Bardonneche ten of these compressors constantly at work, 
each one making three impulses per minute, or 4,320 per day. If the 
charge at each impulse were equal to the capacity of the air chamber, 
the total volume of air compressed daily would be 48,816 cubic metres, 
which, reduced to one-sixth its bulk, would occupy in the receiver a space 
of 8,136 cubic metres. It appears that the volume actually compressed 
amounts to only 23,400 cubic metres, so that the charge in the compres- 
sor is but fifty-four hundredths of one cubic metre at each impulse. 

If we make a comparison now between the results actually reached 
and the compressing force employed, we shall see that the loss in prac- 
tice has proved considerably larger than that which, according to the 
foregoing statements, theory would indicate. . The power of each com- 
pression machine is equivalent to that which would be generated by the 
descent of a vertical column of water twenty-four metres in length and 
sixty centimetres in diameter through a space of four meters, three 
times per minute through the day. 1 The calculation shows that this 

1 The column is not vertical but inclined. The mechanical effect, however, (friction being 
disregarded,) is the same as if it were vertical. The length of the inclined column is greater 
than the vertical difference of level, in the ratio of radius to the cosine of the deviation from 
the vertical. But as the movement of the water in the tube at each impulse is constantly 
four metres in the direction of the axis, the descent in the direction of gravity is diminished 
by the inclination in the same proportion as the length of the column is increased. 

The vertical distance between the levels is twenty-six metres. The rising of the water four 
metres in the short arm of the siphon neutralizes the effect of the four metres at the foot of the 
descending column. But for the influx of water from the reservoir at the top, the driving 
column would be effectively reduced to twenty-two metres. But this inflowing water, filling 
the four metres at the upper extremity of the tube, has a mean descent of two metres, and 
renders the total mechanical effect of the entire descending column equal to that of a ver- 
tical volume of twenty-four metres, as stated above. 

Then, as there are three impulses per minute ; and, as each cubic metre of water weighs one 
thousand kilograms; and, moreover, as the value of one horse-power is ordinarily taken at 
10 I A 



146 PARIS UNIVERSAL EXPOSITION. 

would a little exceed an eighteen horse-power. The whole ten of the 
compressors furnish, accordingly, a horse-power of one hundred and 
eighty. 

seventy-five kilogrammetres per second, or 4,500 per minute, the power of one machine will 
be expressed by 

24 X tmF Xj~X4X 1000 = 18.096 horse-power. 
And as there are ten machines, the total horse power will be 180 90, or 181, nearly. 

The calculations which follow, on the effects of the heat developed in the compression of 
air, or absorbed in its expansion, rest upon established principles of thermotics, which are 
concisely expressed in the following formulae : 

Let v and p be taken to denote, generally, the volume and pressure of any body of air or 
other perfectly elastic fluid, and t the temperature of the same body, as reckoned in degrees 
from the absolute zero — that is, from a point 273° C. below the zero of the centigrade ther- 
mometer. 

Let r , po, and t represent the volume, pressure, and temperature of a particular mass of 
air in its initial condition, and v x , pi, and ti the corresponding properties of the same mass, 
after its condition in some or all of these particulars has been changed. 

Let the ratio of the specific heat of air at constant pressure and at constant volume be rep- 
resented by the letter y. 

Then if the volume of the air changes by expanding against pressure, or by contraction 
under superior pressure, the temperature will also change, unless a certain amount of heat be 
supplied in the first instance or withdrawn in the second. But if, by such means, the tem- 
perature be maintained constant — that is, if, after the change, h =*o, then the following equal 
rions will be true : 

PoT =piVi, and ?2—.^l . 
Pi v 

That is to say, when temperature is constant, pressure is inversely as volume. This 

proposition is commonly known by the name of the LAW of Mariotte. 

It the volume remain constant while the other conditions vary, then 

p ti=pit , and P^jB. 
pi h 

That is, when the volume is constant, the pressure is directly as the temperature 

If the pressure remain constant, while the volume and temperature vary, then 

v ti = vit , and — =- • 

Vi ti 

That is, when the pressure is constant, the volume is directly as the temperature. This is 
called the law of Gay-Lussac. 

Finally, if all three of the conditions vary, while the air neither receives any heat from sur- 
rounding media nor imparts any to such media, we have 



Po 

From whence are deduced the several values of pi, Vu and ti which follow, viz : 



several values of pi, »i, and ti 

These are known as the equations of Poissox. 

The amount of work required to reduce a given volume of air to a smaller volume, answer- 
ing to a given superior pressure, and to force it into a reservoir at that pressure : or. what is 
the same thing, the amount of work which the same mass of air, taken at the superior pres- 



TRANSMISSION OF FORCE BY COMPRESSED AIR. 147 

On supposition that the compression-chambers are entirely filled with 
air at each impulse, this power will not be equal to the work imposed 
upon it. But if, instead of 1.13 cubic metres, there be admitted only 
0.78 cubic metres at each charge, the total resistance will be exactly 
equal to the power. Were not heat developed by the compression, the 
charge might be made as large as 0.94 cubic metres and the total amount 
of daily compression would be 40,608 cubic metres. It would seem, from 
the dimensions adopted, as if the original expectation had been to com- 
press one cubic metre at each pulsation of each machine. Had that 
expectation been realized the compression would have reached to 43,200 
cubic metres daily, reduced to 7,200 cubic metres in volume. 

The power employed is actually capable of compressing 33,860 cubic 
metres daily, to a bulk under the pressure of six atmospheres of 9,500 
cubic metres, becoming by subsequent contraction 5,700 cubic metres. 
But the amount actually compressed is only 23,400 cubic metres daily, 
giving ultimately 3,900 cubic metres of compressed air at the normal 
temperature. This represents a compressing force of only one hundred 
and twenty-five horse-power, being less by fifty-five than the theoretic 
force of the compressors. 

The 3,900 cubic metres at the pressure of six atmospheres are capable 
of producing an amount of work hardly equivalent to seventy-five horse- 
power. There is therefore a loss at Bardonneche, from causes known 
and unknown, equal to seven-twelfths of the hydraulic force employed. 

It is probable that a part of the loss unaccounted for as above may 
be a necessary consequence of this mode of applying the vis viva of an 
inert mass in overcoming elasticity. In order to avoid injury to the 
machine, and also to prevent water from passing along with the air into 
the recipient, the charge must be large enough. The danger is that it 
will be made too large, and that a part of the compressed air will fail to 
enter the recipient. All the force expended upon this portion is thrown 
away. Another part of the loss may be due to the inertia of a body of 
water occupying the bend of the siphon, about two cubic metres in bulk, 
which comes to rest after every pulsation, and opposes the movement of 
the driving column. The same hydraulic power, or an equivalent steam 

sure, is capable of furnishing, in being first introduced into the cylinder of an engine, and 
afterwards expanding to the inferior, may be found by the following formula, in which w 
represents this work: 

y-\ y-l 



(y-1 y-l\ 

x + ^V 1 
(y-l)tfc/ / 



yv 

W=p 1 V 1 l 1-t-— Vlr 1= P iV x ; 



(y-l)*o' 

A formula founded on the law of Mariotte, and which assumes that the temperature of the 
air remains constant during its expansion or compression, has been much used in calculations 
of this nature, but with results necessarily erroneous in proportion as the change of volume 
is greater. It is the following: 



PlVi 



( 1+ "t) 



in which v is supposed to be the larger volume, and the abreviation h. 1. stands for hyper 
bolic logarithm. 



148 PARIS UNIVERSAL EXPOSITION. 

power, would probably be applied more effectually in compressing air by 
moans of pumps, than in the method above described. This the engi- 
neers themselves appear to have tacitly admitted, by introducing pumps 
at the northern entrance of the tunnel. 

It must be finally observed, as having an important bearing upon the 
question of economy in regard to this mode of transmitting power, that 
the work which remains stored up in compressed air, after the important 
deductions we have found it necessary to make, cannot be fully recovered 
without working the air expansively down to the pressure of the atmo- 
sphere. If it has been compressed to six atmospheres, it must be expanded 
more than three and a half times ; if to eight, nearly four and a half ; if 
only to three, to two and a quarter times. At Bardonneche, where the 
perforators work without expansion altogether, half the power is thrown 
away. 

If we apply the results which we have thus reached to the example 
above quoted from the report of the engineers of Mont Cenis, we have 
to make some important modifications of the results there presented. 
The proposition is to carry to a distance of twenty kilometres, by means 
of a tube thirty centimetres in diameter, a force represented by an efflux 
of four hundred and twenty-four cubic decimetres of air per second under 
a pressure of six atmospheres. It is first necessary to recompute the value 
of the power which this discharge is capable of affording. The engineers 
have assumed, what would be true according to the law of Mariotte, viz : 
that the pressure of an elastic fluid is inversely as its density, that each 
litre of the air delivered, as above supposed, would represent a power of 
work equal to one hundred and ten kilogrammetres. Taking into account, 
however, the depression of temperature attendant on expansion, this 
power must be reduced to 61.41 kilogrammetres only. But we must 
increase this again by the amount of force which the air exerts in being 
introduced into the working cylinder of the machine which it operates, 
that is, by the amount of sixty-two kilogrammetres per litre, so that the 
actual force which each litre represents will be carried up to 123.41 kilo- 
gram-metres. A supply of four hundred and twenty-four litres per 
second, with this value, will then furnish a horse-power of six hundred 
and ninety-eight, say seven hundred, but in order to produce it there will 
be required an original expenditure of eleven hundred and seventy-five 
horse-power. 

Since, moreover, it appears that the resistances of the tube will call 
for an increase of the pressure at the source to eight atmospheres, a cor- 
responding addition must be made to this original expenditure. Sup- 
posing the volume of air condensed to remain the same, but to be com- 
pressed as above required to eight atmospheres, the force necessary for 
this compression will be no less than one thousand three hundred and 
fifty horse-power, and the force which the air so compressed would be 
capable of exerting, if used on the spot, would be only seven hundred 
and forty horse-power. At the distance of twenty kilometres, it would 



TRANSMISSION OF FOECE BY AIR AND BY CABLE COMPARED. 149 

fall, as above, to seven hundred ; so that the loss from all causes would 
amount to nearly fifty per cent. 

It is therefore evident that, under the conditions which we have been 
considering, that is to say, in the use of great pressures and tubes of 
moderate dimensions, compressed air does not furnish an economical 
mode of transmitting power. At lower pressures, the original loss is 
less ; and in tubes of larger diameter the resistance in the movement of 
transmission is less. A tube of fifty centimetres in diameter will deliver 
the same volume of air at a velocity but little more than two metres per 
second, and with a resistance of only seven and a half millimetres of 
barometric pressure per kilometre of distance ; which, for twenty kilo- 
metres, amounts to one-fifth of an atmosphere. Supposing this air to be 
originally compressed to three atmospheres, it will deliver a power of 
two hundred and sixty horse at a distance of twenty kilometres with an 
expenditure at the source* of four hundred horse-power. This will be 
sixty-five per cent, of the whole. Of the loss, thirty-five per cent, in all, 
twenty- seven per cent, will be incurred at the point of compression, and 
eight per cent, in consequence of the resistance of the tube. At the 
distance of fifty kilometres, or thirty miles, the power delivered will still 
amount to two hundred and twenty, or fifty-five per cent, of the original 
expenditure. 

It may be interesting to compare this result with that which would be 
obtained in the application of Mr. Hirn's telodynamic cables to the trans- 
mission of a similar power to an equal distance. His allowances for losses 
are two and a half per cent, of the whole power for the resistances of the 
two great pulleys at the termini, and eighty-four kilogrammetres per kilo- 
metre of distance for the fricti on of the pulley supports. To these must be 
added the effect of the resistance of the air and of the rigidity of the cable. 
On four hundred horse-power the first deduction would be ten. The fric- 
tion on the pulley supports in fifty kilometres would consume thirty- six 
horse-power more. For the determination of the resistance of the air to 
the pulleys the data are imperfect, but an approximate estimate may be 
formed by considering that the velocity at the circumference of the pul- 
leys is thirty metres per second, and has been carried to forty metres. 
At thirty metres of velocity the resisting pressure of the air upon a moving 
body is more than one hundred and twenty kilograms per square metre of 
surface directly exposed to it. Each pulley has eight spokes, exposing 
each a surface of three or four one-hundredth parts of a square metre — say 
one-fourth of a square metre in all. If we take the atmospheric resistance 
due only to two-thirds of the circumferential velocity, which resistance is 
fifty-four kilograms per square metre, the force required to overcome it will 
amount to 13.5 kilogrammetres for each pulley, or to twenty-seven for 
the pair of pulleys, and to one hundred and eighty -nine, equal to two and 
a half horse-power, for the seven pairs in a kilometre. Fifty kilometres 
will, therefore, consume one hundred and twenty-five horse-power, which 
added to the consumption above computed for friction, will give a total 



150 PARIS UNIVERSAL EXPOSITION. 

of one hundred and ninety-one. This being deducted from the entire 
original force will leave two hundred and nine horse-power $ the resist- 
ance due to the lateral friction of the air and to the rigidity of the cable 
being still to be allowed for. It follows that, for great distances, the 
transmission of power by compressed air may compete favorably with, 
the only other mode of transmission which could be substituted for it; 
while, for moderate distances, it is economically inferior. For great dis- 
tances, whatever mode of transmission be employed, there must always 
be a very considerable loss. This will be true even with water, whether 
conveyed in canals or in tubes ; while water power can only be so con- 
veyed to points at levels lower than the source. 

There are parts of our country in which the means of transmitting 
power to distances are of high importance. In certain portions of our 
mineral regions the possession of a few hundred horse-power may make 
to a whole community all the difference between x^overty and wealth. 
If this power can be obtained from the distant mountain torrents by 
either of the methods which we have been considering, it is certainly 
better to submit to the loss which they entail than not to obtain it at all. 
There is an incalculable amount of force constantly wasting itself in the 
natural world, which never will or can be applied to any useful purpose 
at the points where it is developed. If the half or the third or the tenth 
part of such a force can be transported into the heart of an industrial 
community, the abstract economy of the means of transportation is a 
matter of secondary importance, provided there are no better means. 
It may, therefore, be justly concluded that the use of compressed air as 
a medium for transmitting power, if not theoretically as advantageous 
as at first thought it might seem, may, under circumstances of not very 
unfrequent occurrence, be an invaluable expedient for turning to useful 
account powers which would otherwise be wholly unavailable. 



CHAPTER IV. 

ACCUMULATION OF FORCE. 

Accumulation of force by compression of water— Sir William Armstrong's 
method — Accumulator of Gouin & Co.— Accumulation in fly-wheels — The 
Mahovos; a contrivance for the promotion of economy in railway trans- 
portation — Its construction — Illustration of the advantages to be derived 
from its use— Application of the Mahovos as a brake. 

ACCUMULATION BY COMPRESSION OF WATER. 

Messrs. Gouin & Co., of Paris, have employed, in certain operations 
of tunnelling, a mode of transmitting power, in which the medium used 
is water under heavy compression. This method has, also, for some years 
been employed in foundries, factories, and other industrial establishments 
in England, for the purpose of storing up the power of a rjrhne mover 
during the intervals in which its work is not required in driving the 
machinery of the establishment for the use of which it was erected. For 
this purpose it was originally introduced by Sir William Armstrong, and 
it was exhibited by him at the London Exposition of 1862. The method 
consists in accumulating a large quantity of water in a strong cylinder, 
placed vertically, and closed by a piston which is heavily weighted. 
The water may be pumped in by the ordinary motor of an industrial 
establishment when it is not otherwise employed, and may be subse- 
quently used to drive one or more hydraulic engines. This mode of 
accumulation is especially useful in cases in which a large power may be 
needed for some particular operations which only occur at intervals, and 
for the sake of which only it would not be consistent with economy to 
provide a motor of adequate power, which could only be made service- 
able at such intervals, and would be required to lie a great part of the 
time idle. A feeble motor may, in an extended time, accumulate a 
hydraulic force of great energy $ and this can afterwards be expended as 
it was accumulated, by degrees ; or, if necessary, all at once. 

This contrivance is evidently not adapted to the general purposes of 
the transmission of power to distances ; for, in the first place, the loss of 
force by friction in the tubes which must be employed to convey the 
water would be very serious; and in the second, since water is practi- 
cally unchangeable in volume by compression, and since the accumu- 
lation in the reservoir cannot be greater than is consistent with the 
security of the reservoir itself there is a natural limitation to the quan- 
tity that can be accumulated. But for working machines at short dis.. 



152 PAEIS UNIVERSAL EXPOSITION. 

tances from the original prime mover, and especially for the working 
of several small machines at different but not very distant points by 
the instrumentality of a single larger one, this expedient may become 
both convenient and economical. Such is the application which has 
been made of it by Messrs. Gouin & Co. in the perforation of tunnels in 
the Apennines. In the construction of these tunnels several shafts 
were sunk at different points along the line. For the purpose of rais- 
ing the earth excavated it Avas necessary to establish elevators of some 
description at each shaft. The constructors resolved to employ cranes, 
actuated by hydraulic engines ; and, in furtherance of this plan, they 
established an accumulator into which water was driven by a single 
steam-engine, where it was compressed to the enormous extent of forty 
atmospheres. 1 

When the force of compressed water is to be employed in the constant 
repetition of a certain effort through a limited space, the simplest and 
most economical mode of application is by direct action. It is in this 
mode that it is employed in such cases by Sir William Armstrong, the 
cylinder of the hydraulic machine being made of a length equal to the 
space through which the effort is required. For larger movements the 
oscillating hydraulic engines of Eamsbottom, already described, are used; 
two cylinders with their pistons acting alternately upon the same shaft. 

In the construction of accumulators a loaded piston, which in its move- 
ment generates a volume equal to that of the water introduced, is. ol 
course, necessary. Were the pressure applied in any other manner than 
by weight, as, for instance, by the elastic reaction of confined air, it could 
not continue to be sensibly constant while the head is drawn down. For 
this reason it will be obvious that, if by the continuance of the action of 
the supply pumps, while no demand is made upon the reservoir, the accu- 
mulation becomes excessive, the piston may become unstable and so 
topple over ; an accident which, considering the enormous weight which 
it carries, would be very serious were it permitted to occur. Two safe- 
guards have been adopted by Sir William Armstrong to prevent such a 
catastrophe. The limiting altitude of safety having been ascertained, 
a connection is established between the piston and a valve placed on the 
induction pipe of the steam-engine working the pumps ; and this provision 
begins to take effect as the limit of safety is approached, and closes the 
valve entirely the moment it is reached. The pumps accordingly cease 
to act, and no more water can be introduced into the reservoir until after 
the supply already accumulated has been to some extent reduced. To 
provide against the possibility of the failure of this contrivance there is 
added a second one, by means of which, whenever the piston rises higher 
than it ought, a stop-cock is opened, and water from the accumulator 
itself is allowed to escape until the proper level is restored. In the accu- 
mulator of Messrs. Gouin & Co. the provision to meet this case of iuse- 

1 In some of the British foundries the pressure in these accumulators is carried up to fifty, 
sixty, and even one hundred atmospheres. 



ACCUMULATION OF FORCE. 153 

curity is particularly deserving of attention. It having been found that 
when water was permitted to escape by a cock there was danger of too 
sudden an arrest of the efflux, in consequence of which the whole machine 
acted like an enormous hydraulic ram, with danger of bursting the cyl- 
inder, or other injury, these constructors gave to their safety-valve the 
form of a piston plunger, which is gradually raised as the level of security 
is passed. This plunger is made hollow, and in one of its sides is a lon- 
gitudinal groove, which gives an increased water-way the higher the 
valve is raised, but which shuts off the water so gradually in the descent 
as to prevent all liability to concussion. 

ACCUMULATION IN FLY-WHEELS. 

THE MAHOVOS. 

Among accumulators of poAver must be classed the Mahovos, a con- 
trivance invented by Captain Carl Yon Schuberszky, a staff officer of the 
Eussian corps of engineers, to promote economy in railway transporta- 
tion and in railway engineering. Captain Schuberszky justly remarks 
that though the railroad system of the present day has attained to such 
a degree of development as to be adequate to provide for the largest 
traffic with pecuniary profit, still it does not yet adapt itself to routes of 
smaller traffic, which, though separately of minor importance, yet, in con- 
sequence of their greater number, are in the point of view of statesman- 
ship most worthy to be fostered. The disadvantage under which the minor 
routes lie is, that the capital invested in them brings no adequate return ; 
so that the possibility of their maintenance, or even of their original con- 
struction, must depend, in many cases, on the possibility of reducing 
within a moderate limit both the cost of laying the way and that of ope- 
rating it after it is laid. The main cause of the expensiveness of railways 
is the irregularity of the earth's surface. In a country, if such an one 
could be found, over which there should prevail from one end to the 
other a uniform dead level, railroads would be cheap enough to pay for 
construction upon almost any route. But wherever inequalities exist, 
and that is almost everywhere, these must be overcome by expedients 
which are all costly, and between which it is sometimes difficult to choose. 
These expedients reduce themselves to three, viz : 

1. To reduce the inequalities, by cutting through hills and filling up 
hollows, at whatever cost. 

2. To evade the inequalities, by giving to the road a serpentine track. 

3. To permit the inequalities to remain, reducing them only within a 
certain determinate limit of inclination. 

Of these three possible modes of proceeding the first is the most costly 
per linear mile of way constructed; and when the inequalities are heavy, 
and especially when the cutting is in rock, it is usually too costly to be 
adopted except where there exists a certainty of a very remunerative traf- 
fic. Nevertheless, in general, as a road constructed on this plan will be 



154 PAEIS UNIVERSAL EXPOSITION. 

the shortest possible, and most nearly level, (quite level, indeed, if the ter- 
mini are at the same elevation as referred to a horizontal plane,) the 
cost of operating the road after its construction will he minimum; both 
because its stations will he fewest and because the wear and tear of its 
rolling stock will be least. 

The second plan reduces the prime cost of construction per mile of 
the road, but increases its length, and introduces curves, which are dis- 
advantageous both by increasing the cost of maintenance and retarding 
the rapidity of movement. The increase of length may be more or less 
nearly an offset to the diminution of the original cost of a given length : 
so that, on this side, the saving may be more in seeming than in fact : 
but. at any rate, the increase in the cost of working and maintenance is 
very real : so that here the seemingly and possibly really cheaper road 
will prove in the end to be the most expensive. 

As to the third plan, that of pursuing a nearly direct line with as little 
cutting and filling as possible, and replacing deep cuts and heavy fills 
by steep gradients, it keeps down the prime cost of the road per 
mile without increasing its length, and without admitting troublesome 
curves : but. on the other hand, it makes it an impossibility for a given 
locomotive any longer to draw the weight of train which, on a level road. 
constitutes its regular charge. The maximum load which the engine can 
drag up the steepest grade, is its maximum load for the whole way. But 
on a well constructed road, in good condition, the resistance to traction 
is donbled on a rising gradient as low as twenty feet to the mile. There 
are few roads which have not. in some portions of their length, gradi- 
ents of forty or titty feet to the mile: and many admit them much 
higher. All such roads, therefore, employ engines which, upon a hori- 
zontal track, could take much heavier trains than those with which they 
are actually charged. It follows that these engines have, over the 
greater part of the route, a surplus power, which may. indeed, be econ- 
omized by keeping down the steam, but which cannot be employed use- 
fully. 

The question naturally arises, might not this surplus be expended in 
accumulating a store of power in reserve, to be applied in subsequent 
aid of the engine over the difficult parts of the way ! 

Again, as it happens on these ordinary roads with inchned gradients 
that the inclination will usually be descending as often as ascending: 
and as a train will run down a gradient of very low pitch by the effect of 
it> own unaided gravity, so that in fact not only is it necessary in such cases 
to shut off the steam from the engine, but even also to apply the brakes 
in order to prevent a dangerous acceleration, it may be further asked 
whether the immense living force which the train thus acquires on a 
descending grade may not in some manner be accumulated and saved. 
so as to be usefully employed in assisting to overcome the next ascent. 

These are cpuestions which Captain von Schuberszky has been making 
the subject of long continued study and experimental investigation: 



ACCUMULATION OF FORCE— THE MAHOVOS. 155 

and the result is the machine which is named by him the Mahovos. 
Having been commissioned by his government to visit and carefully 
examine the various European railways into the construction of which 
heavy gradients have been admitted, and having personally acquainted 
himself with all the particulars of economical interest relating to them, 
and satisfied himself of their serious disadvantages, he was led to turn 
his thoughts toward a possibility of a remedy. It first occurred to him 
to employ the force developed in the train on a descending grade by 
gravity, in compressing air, with a view to apply the elastic force of the 
air so imprisoned in overcoming subsequent ascents; but in this his 
success did not satisfy his hopes, and, as an alternative idea, he deter- 
mined to try the principle of the fly-wheel. 

The Mahovos, then, is a fly-wheel, or, more properly, a pair of fly- 
wheels, and nothing more. The peculiarity of these wheels is that they 
are singularly heavy. They are provided with an independent truck of 
their own, which is introduced into the train immediately behind the 
engine. The truck has three pairs of running wheels approaching each 
other very nearly by their circumferences. In the intervals between 
these wheels are placed two pairs of friction wheels resting immediately 
on them, as cannon shot are piled upon one another in a magazine ; and 
in the interval between these rests upon their circumferences the large 
axis of the Mahovos; the huge fly-wheels themselves overhanging the 
truck upon the two opposite sides. This pyramidal structure is reduced 
in height and rendered more stable, by giving to the middle pair of run- 
ning wheels a diameter considerably less than that of their neighbors, 
and the friction wheels are made of such size as to run close to each 
other without touching. 

It is easy to understand now the effect of this arrangement. When 
the train moves, the running wheels impart motion to the friction wheels, 
and the friction wheels transfer this movement to the fly-wheels. The 
diameters of the wheels, and that of the axis of the fly-wheels where it 
rests upon them, are so related that a velocity of thirty kilometres (18.6 
miles) in the train will generate in the circumference of the fly-wheel a 
rotary velocity of one hundred and forty-two metres (466 feet) per sec- 
ond ; and as the fly-wheels themselves weigh 26,000 kilograms (say — 26 
tons) it is computed that, with this velocity, they will embody a living 
force of more than twenty million kilogrammetres, or one hundred and 
forty-four million foot-pounds. 

In order that this great velocity in a mass of such magnitude may not 
cause the bursting of the wheels by centrifugal force, the material used 
in their construction is cast steel ; and Captain von Schuberszky asserts 
that they may safely be run five times as fast as any similar wheels con- 
structed of cast iron. The casting of the massive perimeters is not made 
in a single ring. Apparently, from the description, they are fashioned 
somewhat as Mr. Krupp constructs cast-steel tires, viz., by splitting an 
ingot in the middle, opening it out and bringing it to the circular form 



156 PARIS UNIVERSAL EXPOSITION. 

by hammering and rolling. Three separate rings thns formed are 
shrunk on to each other, the surfaces in contact having corresponding 
concavity and convexity to secure firm connection without the use of 
holts. The axles of the fly-wheels, where they rest on the friction wheels, 
are protected by steel rings, in order to admit of renewal after wear 
without a change of the axle itself. 

The friction wheels are also made of cast-steel, or of cast-iron with 
steel tires. Their surfaces are somewhat rounded like the band wheels 
of a lathe. In order to afford relief against sudden shocks, the axes of 
the extreme running wheels have boxes which yield to a slight extent 
horizontally, being backed by compacted rubber. 

The effect of atmospheric resistance to rotation is reduced as low as 
possible by applying flat plates of iron to the lateral surfaces, which 
plates, are secured in place by angle-iron, thus shutting in the spokes and 
making of each wheel a kind of drum. And as a security against acci- 
dents from the contact of persons or things with the wheels while in 
rotation, they are further enclosed within sheet iron boxes which serve 
as shields. 

As the train moves from rest the velocity of the fly-wheels is gradually 
accelerated, and it attains finally a maximum which corresponds to the 
maximum velocity of the train. If now the steam is shut off from the 
engine, the fly-wheels themselves become a source of driving power, and 
they will maintain the movement until they have given back the work 
stored up in them precisely as it was at first received. But suppose it 
to be desired to stop the train without expending the accumulated force ; 
this may be effected by a mechanism which allows the friction- wheels 
to be raised out of contact with the driving-wheels, while the fly-wheels 
continue to revolve without interruption. In stopping for brief inter- 
vals at stations, there is thus not only no material loss of power, but in 
starting anew it is not necessary to expend force in again putting the 
fly-wheels into motion. But when the stop is to be for a length of time, 
the steam may be shut off at a distance before reaching the station, such 
that the force of the machine may suffice to carry the train to the end 
and exhaust itself in the process. 

In illustration of the advantages to be derived from the use of this 
contrivance, Captain Yon Schuberszky considers the case of a freight 
train drawn with a maximum velocity of thirty kilometers, or say nine- 
teen miles, an hour, by a locomotive of forty tons, with all its wheels 
coupled as driving-wheels. The resistance of the train on a level being- 
taken at 0.004, and the force of traction at one-sixth the weight on the 
driving-wheels of the locomotive, we have, for a train whose weight is Bff, 
and a locomotive whose weight is m, running on a road whose maximum 
gradient is n, the equation — 

! = M(0.004+tt). 

Supposing the value of p to be forty tons, and the maximum gradient 



ACCUMULATION OF FORCE THE MAHOVOS. 157 

one in a hundred, or say fifty-three feet to the mile, we shall find the 
value of M, or of the heaviest load which the locomotive can draw up the 
grade, by making these substitutions, thus : 

6.667 =M (0.004+0.01), 
whence, 

M = 476.143 tons. 

But though this is a load to which the engine is equal under favorable 
circumstances, a considerable allowance must always be made for the 
possibilities of contrary winds, a track obstructed by snow, &c, <&c, or 
for the occasional imperfect adhesion of the driving-wheels to the rails 
in consequence of moisture or ice. It is not considered safe to charge an 
engine with a load beyond about eighty per cent, of what it might per- 
haps carry through safely nine times out of ten, since the inconvenience 
and confusion which would be caused by the failure in the tenth instance 
would far overbalance the advantage gained by carrying a heavier load 
the nine times preceding. 

The maximum allowable weight of a freight train on a road of maxi- 
mum gradient of fifty or fifty-five feet to the mile, is then to be taken 
not higher than three hundred and eighty tons, in which weight the loco- 
motive is included. 

If, nevertheless, to such a train we add the Mahovos, of which the 
weight with that of its truck amounts to forty tons more, we shall not in- 
cur the liability to delay or stoppage which such an addition to the weight 
of the freight cars would occasion, since this machine itself carries with 
it a provision for preventing such accidents. If the rails are slippery in 
any place, and the adhesion of the driving-wheels of the engine is insuf- 
ficient to maintain the movement, the wheels of the Mahovos supply an 
additional driving power equal for the time to that of the engine, so 
that the train will move with half the ordinary force of adhesion. It 
would be possible, therefore, to carry up the weight of the train to four 
hundred and fifty or four hundred and sixty tons by adding thirty or 
forty tons more of freight cars, and still incur no serious danger of 
stoppage. 

The stoppage in such a case, should it occur, will occur probably on 
the inclines. If the weight of the train is not increased above four hun- 
dred and twenty tons it will be possible for it to ascend an incline steeper 
than that which has been supposed ; that is to say, steeper than fifty- 
three feet to the mile, or one in a hundred. For since, on the incline, if, 
as usual, it is not of great length, both the engine and the Mahovos 
may be applied as motors, there will be twice as much power of trac- 
tion as in an ordinary train, or in all an adhesive force represented by 
6.667 x^ = 13.334 tons. From this we may still make the deduction 
usually made as a security against accidents, of twenty per cent, of the 
power of traction of the locomotive, viz : 6.667 x 0.20 = 1.3334, and 
there will remain, notwithstanding this, the large available total of 
twelve tons. For short ascents the living force of the train itself may 



158 PARIS UNIVERSAL EXPOSITION. 

be counted on as a help; as in fact, in actual practice, it often is by skilful 
engineers. This at the velocity of thirty kilometres, or 18.6 miles per 
hour, (8.265 metres, or 26.327 feet per second,) will give a living force in a 
train of four hundred and twenty tons, amounting to 1,462,600 kilogram- 
metres, or 10,565,000 foot-pounds, which is more than the fifteenth and 
less than the fourteenth part of the living force of the Mahovos as given 
above, and will therefore add in effect about 0.4 of a ton to the power of 
traction. The total power of traction will then be 12.4 tons, and the 
inclination of the gradient up which it will drag the train may be found 
by resolving, with respect to n, the equation, 

12.4 = 420 (0.004 x n). 

The resolution gives n = 0.0255, which is equivalent to a gradient of 
one hundred and thirty-five feet to the mile. 

The next question is, how far will the accumulated force drag the 
train up such an incline as this ? And here it must be remembered that 
the locomotive itself will take the train up a gradient of 0.012 ; so that 
the accumulated force will only have to contend against the excess of 
the gradient 0.0255 above this; that is, against an incline of 0.0135. 
This represents the ratio of the resistance of the train to its absolute 
weight, and consequently the total constant resistance is equal to 
420 x 0.0135 = 5,670 kilograms. 

On the other hand we have — 

Kilogramraetres. 

Living force of the Mahovos 20, 875. 250 

Living force of the train 1, 462, 590 

Total 22. 337. 840 

Hence, if D be the distance to which the train will be carried up an 
incline of one hundred and thirty-five feet to the mile throughout its 
whole extent, we shall have — 

D = 2 \ 3 y^ = 3,922 metres : 

that is, nearly four kilometres, and about two miles and two-fifths. 

This, however, would exhaust the force entirely. If we consider it 
expedient to retain an ultimate velocity of nine and a half kilometres, 
or say six miles per hour, the available living force will not exceed 
20,000,000 kilogrammetres, which will give — 

-p. 20,000,000 „ ™ , 

L> = — 1 ^~ Ti — = 3,o2 1 metres ; 
o,6<0 

or three and a half kilometres, equal to two and a sixth miles. 

On a grade of which the mean inclination is one hundred feet to the 
mile, or 0.019, the distance passed over iu reducing the velocity of the 
train to six miles an hour would be nearly seven kilometres, or four and 
a quarter miles. 

In leaving a station upon a level track the excess of power in the 
engine operating on the fly-wheels will bring up the living force to 



USE OF THE MAHOVOS AS A BRAKE. 159 

about half its maximum in going two kilometres, or a mile and a quar- 
ter. This will correspond to the mean velocity of the train taken at 
twenty kilometres, or twelve and a half miles per hour. To bring it to 
the maximum, the train must move over two and a quarter times this 
distance. 

Supposing successive grades of ascent and descent to be encountered, 
it is evident that as in the ascents the living force of the Mahovos is 
diminished by gravity, so in the descents it is increased. And since, 
on any descending gradient exceeding 0.004, or twenty feet to the mile, 
the train will run down itself, so that in ordinary practice it is not only 
necessary to shut off the steam, but likewise to put on the brakes, this 
machine, by absorbing the force* usually wasted on the brakes, becomes 
a means of storing up the force of gravity itself 5 so that on a regularly 
undulating road on which it should be introduced, the engine would be 
required to do no more work than on a level. Moreover, in preventing 
without the use of brakes the train from acquiring an excessive velocity 
on a downward grade, it saves much wear and tear of rolling stock, and 
does away with the necessity of employing an army of brakemen upon 
every train. 

In approaching a terminal station the fly-wheels may be allowed to 
expend their living force entirely. Supposing them at a maximum 
velocity and the track to be level, steam may be shut off more than 
thirteen kilometres, or eight miles before arrival. As this, however, 
would reduce the final velocity too far, it is best to shut off steam at 
about six miles before arrival, and to apply the brakes at the end. 

At intermediate stations it is estimated that the Mahovos will lose, 
by friction on the axles of the supporting wheels, 80,000 kilogrammetres, 
or 580,000 foot-pounds of living force, every minute. Supposing the 
stop to continue ten minutes, there will be a total loss of 800,000 kilo- 
grammetres, or 5,800,000 foot-pounds, which is only about two per cent. 
of its maximum amount. 

In starting anew, the machine must be sustained out of contact with 
the driving wheels until a velocity has been acquired in the train corre- 
sponding to that which belongs to the rate of motion of the fly-wheels 
at the time, and must then be put again into connection with the run- 
ning wheels. Should there be a discrepancy of rates between the train 
and the Mahovos, the running wheels will slide for a short distance on the 
rails ; but it is easy to contrive indicators attached both to the wheels of 
the locomotive and to those of the Mahovos, which shall show their rela- 
tive rates ; and which, being both under the eye of the attendant, shall 
inform him when it is proper to make connection. 

There is one use of the Mahovos which the inventor presents as capa- 
ble, under certain circumstances, of being highly advantageous. It has 
been shown how this contrivance may be employed to fulfil the function 
of a brake on a descending grade. But, by the aid of an additional 
attachment brought into use only on extraordinary emergencies, it may 



160 PARIS UNIVERSAL EXPOSITION. 

be made to act with great power as an instantaneous brake. For this 
purpose, on the axes of the friction wheels which sustain the Mahovos, 
there is a second pair of wheels somewhat smaller, and nearer the 
middle, which ordinarily run out of contact with anything. But the 
axis of the Mahovos above them carries a pair of eccentric rings, run- 
ning loose upon it, which, when turned with the thicker part downward, 
wedge themselves, as it were, between the wheels above spoken of and 
the axis of the Mahovos, lifting the latter out of contact with the fric- 
tion wheels. 1 

If the eccentrics can move no further, the fly-wheels continue to turn 
freely in them, but they no longer drive the running wheels of the truck. 
On the contrary the whole weight of the fly-wheels rests, through the 
eccentrics, as a brake upon the running wheels, and prevents them from 
turning at all. The force which the Mahovos thus opposes to the move- 
ment of the train is the sixth part of its own weight ; and if the engine 
be reversed at the same time, and the brakes of the tender be put on, the 
total force of the resistance will amount to 16,667 kilograms. If the 
train is moving with a velocity of eight and a quarter metres per second, 
which is the assumed maximum, this is sufficient to carry it directly 
against gravity to a height expressed by li in the equation 

v 2 
h = — =3.51 metres. 

v being the velocity of movement, and g the force of gravity, repre- 
sented by 9.808 metres. 

But the resistance 16,667, is only the twenty-fifth part of the weight 
of the train, and hence the living force in the moving mass would carry 
it twenty-five times as far against this resistance as against gravity. In 
other words, after the application of the Mahovos brake, the train would 
stop in 3.51 metres multiplied by twenty-five. 

3.51x25=88.5 metres=290.28 feet=100 yards nearly. 

The train can thus be stopped in twenty seconds, an important 
advantage in case of any suddenly perceived misplaced switch, open 
draw-bridge, or obstruction on the track. 

The presumed advantages of the employment of the Mahovos are 
briefly summed up as follows : 

1. Diminished cost of ways in consequence of the admission of steeper 
grades than are now allowed. 

2. Beductionof the amount of curvature and increase of the minimum 
radius, by which the mean velocity of movement may be improved and 
wear and tear diminished. 

ir The manner of effecting this change is very simple. The two eccentric rings "are con- 
nected with a heavy weight in the form of a cylinder, extending from one to the other 
parallel to the axis of the Mahovos, and attached to the thick side of each. This weight is 
sustained on a level with the axis, or higher, by a support which admits of being instanta- 
neously withdrawn. The heavy cylinder then falls, and by its mere weight wedges the 
rings beneath the axis of the Mahovos, with the consequence described in the text. 



ADVANTAGES OF THE USE OF THE MAHOVOS. 161 

3. Since the original construction of the substructure is simpler, the 
cost of maintenance will be less. 

4. As the rails and the wheels are less frequently subjected to wear by 
the brakes, they will be more durable. 

5. The use of the Mahovos as an instantaneous brake may prevent 
grave accidents, such as are often attended with destruction of property 
and loss of life. 

6. Economy of fuel is greatly promoted by the use of this auxiliary to 
the engine, 

The account here given of this invention has been extended beyond 
the original intent, because, on an examination of its principles, it has 
seemed to embrace the germ of a real improvement. At first view, 
the impression produced by it was decidedly unfavorable ; and it seemed 
as if the burden it would impose on the motive power would be more 
than an offset to the benefit it could render. Careful study has 
removed this impression and produced the conviction that the invention 
is capable of being made very substantially useful. 

The question how great or how small may be its real value will not, 
however, long remain a matter of conjecture. It has already been tried 
by the inventor on the railroad from St. Petersburg to Warsaw ; where, 
as he asserts, the fact has been practically established that, with its 
help, a double train can be carried the whole way. In Eussia it has 
attracted flattering attention from railroad engineers and railroad direc- 
tories ; and a company has been formed under the presidency of Baron 
von Delwig, inspector general of all the Eussian private railways, for 
the purpose of thoroughly testing its value in practice. 

In the Exposition the Mahovos was illustrated by a very pretty model, 
which descended an incline of four to the hundred, for a distance of one 
or two hundred feet, the fly-wheels absorbing the force of gravity in the 
descent; and then after being reversed on a turn-table, dragged its train 
again to the top. The train was made up of box cars or tanks loaded 
with water. 

The agent in attendance handed to visitors a card, which was probably 
not prepared by the inventor, containing the statement that the machine 
after descending the plane and being reversed on the turn-table, "would 
easily draw the train to the top of the same incline, still preserving 
much velocity in the fly-wheels, even though a man should mount upon 
the cars." This was saying more for the Mahovos than the inventor 
claims ; and yet the result, which seemed to surprise nobody in the wise 
looking crowd which daily gathered to witness it, bore out the assertion. 
The Mahovos took the train to the top, and took the man also. In seek- 
ing for the solution of this phenomenon, it was presently perceived that 
in the descent of the train, the attendant followed it, and added to grav- 
ity all the force he could exert by pushing it from behind. The source 
therefore of the excess of power which the machine still preserved, after 
ascending the plane and carrying up the man, was no longer a mystery. 
Hi A 



CHAPTER V. 

MEASURE OF FORCE. 

Mechanical contrivances for measuring the force of prime movers — Prony's 
friction dynamometer — taurines's dynamometer — method of registering its 
indications — Bourdon's dynamometer— Hi rn's pandynamometer — Torsion of 
driving-shafts— the distortion of parts of machines made to indicate the 
amount of strain — two methods of accomplishing the result; the mechan- 
ICAL and the electrical— Importance of this invention to the mechanical 

ENGINEER. 

DYNAMOMETERS. 

Mechanical contrivances for measuring the force exerted by a prime 
mover, or the amount of force consumed in driving a machine or all 
the machines of an industrial establishment, have been constructed in 
various forms. They involve generally the expedient of interposing 
between the motor and the machine, as a medium through which the 
power is to be transmitted, some combination of springs, or some mech- 
anism of which springs are the essential parts, provided with a scale on 
which are marked the degrees of static force corresponding to different 
states of tension, and sometimes also with automatic machinery for 
making periodical record of the marking of the index on the scale. 
Many of these contrivances have been long in use and are sufficiently 
familiar, and every Exposition brings forward one or two more. 

peony's friction dynamometer. 

Simpler than any of these is the friction brake of Prony : and but for 
certain disadvantages necessarily attendant on its use it would possess 
a superiority from which no other contrivance could displace it. This 
contrivance, as is well known, is unadapted to the measurement of a 
power which is at the same time usefully employed. In other words, it 
is unsuited to the determination of a force which is actually transmitted 
to a machine ; it can only measure one which is generated in circum- 
stances as nearly similar to those in which the machine is operated as by 
the most careful precautions they can be made : and this force is then 
assumed to be equivalent to the former one. The Prony dynamometer 
cannot be employed for the purpose desired without loss of time, and 
without the expense attendant on an unproductive application of power. 
Moreover, when motors are of great magnitude, the heat developed by 
the friction of the brake, and the rapid wearing away of the material, 
make it impossible to protract the experiment sufficiently to obtain 



MEASURE OF FORCE — PRONY's DYNAMOMETER. 163 

results entirely satisfactory. With such motors, also, there are dangers 
of accident from irregularity of movement, the consequence of the elas- 
ticity of the parts intervening between the motor and the brake, which 
may sometimes be attended with serious consequences. A dynamome- 
ter, on the other hand, which serves only as a medium of transmitting 
force without consuming it, and which, without occupying an inconven- 
ient amount of space, may be permanently attached to the machine, will 
possess the very great advantage of showing the expenditure of force at 
all times, without requiring any special attention from the engineer or 
other attendant. It is to be desired that such a contrivance shall not be 
itself a charge upon the power ; that is, that by its interposition the 
expenditure of driving force required shall not be sensibly increased. 
This property belongs to all that class in which the power of the motor 
acts directly with all its force to produce flexure in springs, while the 
springs by their effort of recoil transmit it undiminished to the machine. 
It is evident that there must be a limit to the applicability of this prin- 
ciple which will very soon be reached. As the power to be transmitted 
is made greater, the strength of the springs through which it is trans- 
mitted must be correspondingly increased. But this involves the neces- 
sity of making them heavier in similar proportion, so that they may soon 
become unwieldy and undesirable attachments to the moving parts of a 
machine. This objection may to a certain extent be evaded by giving 
to the springs such a form and such a position in the apparatus that the 
force of the motor shall be exerted mainly against their power of resist- 
ance to extension or compression, and only partially against their elas- 
ticity. Thus, if we give to a bar of tempered steel the form of a horse- 
shoe, the force required to change its curvature by a definite amount, 
applied in the direction either to straighten it or to bend it still more, 
would be greatly less than would be necessary to produce a similar 
degree of change in the form of the same bar on supposition that it had 
the original shape of an archer's bow. Dynamometers, therefore, which 
are designed to transmit force on the principle here considered, allow 
the force to act wholly in producing flexure only when it is small ; those 
designed for use in connection with steam-engines or other motors of 
considerable power being constructed in such a manner that the elasti- 
city of the springs acts at a mechanical advantage. 

TATJRINES'S DYNAMOMETER. 

A dynamometer of this kind was exhibited by Mr. Taurines, of Paris, 
which was simple and well adapted to engines of moderate power. It 
forms, if desired, a permanent part of the connection between the engine 
and the machine driven ; and in this case the shaft of communication is 
constructed with a joint formed by inserting one length within the other, 
in the manner of tenon and mortise. Two arms are attached to the 
part of the shaft on either side of this joint, in a radial direction ; those 
on the same side being diametrically opposite to each other, while those 



164 PARIS UNIVERSAL EXPOSITION. 

of each pair are ninety degrees from those of the other. Stout springs 
in the form of circular quadrants connect the extremities of these arms 
on two opposed quarters of the circle, and the force of the motor is trans- 
mitted through these springs by a pushing effort. The effect is to bend 
the arches outward, and the degree of this bending is indicated by a 
spring which connects their middle points. The flexure of this spring 
is diminished, and in straightening it moves an index in the direction of 
the axis of rotation. 

Mr. Taurines has added a very ingenious mode of registering the indi- 
cations of the dynamometer, and, generally, of summing up the total 
amount of work done, (or, rather, of force transmitted from the motor,) 
during a continuous period of operation. This is, in fact, a modification 
of the planimeter of Oppik offer, elsewhere described. The motion of the 
dynamometer index parallel to the axis of rotation is magnified and 
transferred, by suitable mechanical arrangement, to a little car running 
on a railway. Tta car sustains a solid cone, rather acute, and placed in 
such a position that one of its generating lines is horizontal. This cone 
is kept in rotation by the machine, with an angular velocity the same as 
that of the motor shaft, or definitely related to it. On the horizontal 
side of the rotating cone rests a little sphere, which is held between the 
two arms of a fork, being immediately sustained by two small caps, with 
spindles attached, like the stems of acorn cups, which serve as axes of 
motion. The sphere turns on the cone by friction, and its rotations are 
transmitted by one of the little axes just spoken of to a set of register 
dials. As the energy of the transmitted force increases or diminishes, 
the car moves forward and backward along its track, presenting to the 
sphere resting upon it a larger or smaller circle of contact. While there- 
fore the velocity of rotation of the cone is constantly the same as that of 
the motor shaft, or in an unvarying ratio to that velocity, the rotation 
of the sphere is accelerated as the base of the cone is brought more 
nearly beneath it, and retarded as the vertex approaches. It is evident 
that a roller with a rounded periphery would answer as well as a sphere, 
the object being only to obtain a contact which shall be virtually a point : 
but, as by constantly running on the same circumference the surface of 
contact would be enlarged, a sphere is used so sustained that the longi- 
tudinal motion of the cone may give it a compound rotation, and thus 
change continually the circumference exposed to wear. 

This dynamometer, when constructed with a view to be displaced and 
attached to other machines, will have, of course, proper connections by 
which its two opposite parts maybe secured to the corresponding shafts 
of the motor and the machine operated upon. 

A connection of this kind might suffice for steam-engines or other 
motors of moderate horse-power; but it is obvious that a limit to its 
availability must be soon reached, so that for motors of great energy no 
spring dynamometer will serve. The only expedient which presents 
itself, therefore, under these circumstances, seems to be to connect the 



MEASURE OF FORCE — DYNAMOMETERS. 165 

motor with the machine through some intermediate gear work, and to 
devise some method by which the effort passing through this gear work 
may be measured. 

bourdon's dynamometer. 

Such a dynamometer is exhibited by Mr. Bourdon, of Paris, which 
may be briefly thus described. Parallel to the direction of the shaft of 
the motor are established two other shafts, each carrying a gear wheel, 
by which they act on each other. One of these shafts is connected by 
band or gearing with the motor, the other transmits the movement simi- 
larly to the machine. The shaft connected with the motor is capable of 
no motion except that of rotation ; the other has a certain freedom of 
displacement in its bearings, longitudinally. The teeth of the two gear 
wheels are slightly spiral. The effort of the motor tends not only to turn 
the movable arbor, but also to displace it in the direction of its own 
length. If no resistance were opposed to this displacement, it would 
immediately find its limit, and the arbor would then have only a rotary 
motion. The displacement, however, is opposed by a spring, and it takes 
place only so far as to bring about a condition of equilibrium between 
the resistance of the spring and the element of the driving force which 
is directed longitudinally. The value of this element will depend upon 
the degree of obliquity of the teeth of the spiral gearing to the axis of 
rotation. If their surfaces are parallel to the axis, there will be no lon- 
gitudinal displacement. And whatever be the angle of inclination, the 
longitudinal force will bear a calculable and constant ratio to the total 
force exerted by the motor, so that by measuring this fraction of it we 
in effect measure the whole. A scale must be adapted to a dynamo 
meter of this kind by a series of experiments, in which static forces of 
torsion may be substituted for the action of a motor. 

The dynamometer of Mr. Bourdon is founded on a principle which was, 
it is believed, first employed by an American inventor — Mr. Neer, of New 
York — in an instrument of this kind patented by him ten or twelve years 
ago, and exhibited at the Exposition of 1862, where it was honored with 
a medal. In this the wheels or pulleys of the dynamometer were upon 
the same shaft, one being fixed and the other free; and the displacement 
of the loose pulley took place in consequence of the action of fixed arms 
upon the other, acting upon inclined surfaces upon its opposed lace. It 
had also an automatic registering apparatus, a very important addition 
to such an instrument, and one which is almost indispensable to its use- 
fulness in practice. 

hirn's pandynamometer. 

The most ingenious form of dynamometer which has ever yet been 
presented, is one which was exhibited at the Exposition of 1867, by Mr. 
G. A. Hirn, of Logelbach, on the Ehine, and called by him, from its uni- 
versal applicability, a pandynamometer. It is founded on the idea of 
making the machine itself, of which the performance is to be tested, the 



166 PARIS UNIVERSAL EXPOSITION. 

instrument of measuring its own work, through the distortion produced 
in it by the transmission of the driving power. 

Whenever a force which originates at one point is applied at another, 
to the overcoming of resistances by means of any system of solid con- 
nections, these solids must necessarily, for the time being, change their 
form. When, as is usually the case with powerful motors, the transmis- 
sion is made by means of a revolving shaft, the shaft will undergo torsion 
to an extent proportional to the resistance which opposes its revolution; 
and if this torsion can be measured, it may be the means of measuring 
the power of the motor itself. This is what the pandynanionieter of Mr. 
Hirn proposes to do. 

Previously to observation, it might seem impossible that the massive 
iron shafts used to drive the machinery of foundries and factories, or the 
helices which propel our great ocean steamers, could possibly change 
their figure sufficiently to answer the purposes of the proposed deter- 
mination ; but when the question is subjected to the test of careful experi- 
ment, it is demonstrated that the torsion of the strongest shaft, under 
the great strain to which it is subjected, is a quantity quite measurable. 

It is of course desirable that the indications of the dynamometer 
should be as large as possible, and therefore in applying the principle of 
Mr. Hirn, and making the machine tell its own story, it is best to select 
upon the shaft whose torsion is to be measured, two points as far apart 
as convenience will allow. To these parts are adapted pulleys or gear- 
wheels, which are designed to operate a recording apparatus which 
serves to register, periodically, the condition of the shaft as to torsion. 
In order that these wheels may be attached without in any manner dis- 
turbing the arrangements of the machine, they are constructed in halves 
so as to be applied on opposite sides of the shaft and bolted together. 
It would be impossible, without detailed drawings, to describe the exact 
manner in which Mr. Hirn proposes to obtain the indications desired. 
He has two independent modes, in fact, in which he accomplishes the 
object ; one of them being mechanical and the other electrical. With- 
out, however, explaining his actual process, it is easy to illustrate the 
possibility of obtaining the proposed result on either of the two princi- 
ples. Let, for example, a metallic cylinder covered with paper suitably 
prepared for the purpose by chemical means, be kept in rotation by the 
motor, and let the end of an insulated metallic wire rest upon the sur- 
face of this paper, while the other end is connected with one pole of a 
battery. Let connection also be made between the metal of the cylin- 
der and the other pole, If with these arrangements the battery is sup- 
posed to be charged, the wire will trace a visible line upon the paper. 
If we now cut the wire and carry its divided extremities to the axis of 
the motor at one of the points fixed on for observation, and if we there 
attach an insulating band to the axis itself, and over this apply a nar- 
rower metallic band on which one of the wire ends may rest as a tangent 
while the other is made a similar tangent to the portion of the non-con- 



MEASURE OF FORCE — HIRE'S PANDYNAMOMETER. 167 

ducting substance which the metal does not cover, then all that is neces- 
sary to cause the circuit to he closed at every revolution of the shaft, is to 
introduce into the non-conducting ring a very narrow strip of metal in 
contact itself with the metallic ring. As this slip passes under the tan- 
gent wire last mentioned, the circuit will be for an instant complete, and 
a dot will be made upon the chemically prepared paper. Now sup- 
pose that the wire which rests on the paper has two branches by which 
it communicates with the battery $ and let the second branch be treated 
as we have supposed the first to be ; only that the two ends formed by 
cutting it are carried to the second point of observation on the shaft; 
and let the arrangement of the rings on the shaft be such that when 
there is no torsion, or when the shaft is turning without resistance, the 
two contacts shall be made simultaneously. It is evident that there will 
be but one mark produced upon the cylinder. If, however, the axis is 
twisted by the effort of the motor and the opposed resistance of the ma- 
chine, the contact at the end near the motor will take place first, and 
that near the machine after a minute interval which will depend for its 
value upon the amount of torsion. Instead of a single spot therefore 
upon the paper there will be two spots ; and the distance between them 
will furnish an indication of the force which is being at the time trans- 
mitted through the shaft. It may be observed that the distance of the 
two marks from each other in angular space may be magnified by giving 
to the cylinder which receives the record a velocity of rotation exceeding 
that of the working shaft. Or a mechanism may be attached to the shaft 
which shall gradually accumulate the values of the successive intervals for 
many successive revolutions, and shall indicate the result by marks occur- 
ring, for example, at the end of every fifty or one hundred. This last 
is the method employed in fact by Mr. Hirn, the actual record made by 
his machine multiplying the actual torsion fifty times. It is easy to see 
how a mechanical mode of registration might be substituted for the one 
which has been described. Without attempting to give Mr. Hirn's con- 
struction, which is not that here suggested, it may be simply observed 
that if, instead of bands attached to the shaft for the purpose of pro- 
ducing periodical electrical contacts, we suppose cams of what is called 
the snail-form to be substituted, two springs resting on these cams so as 
to fall simultaneously in the absence of torsion, would fall successively 
when the shaft is twisted ; and the mechanical force exerted by such 
springs might be made to determine the simultaneous fall of marking 
points upon the revolving cylinder. It is only to be added, that, in case 
a record of the performance of the motor is to be maintained for a length 
of time, the cylinder of record, or the marker itself, should receive a 
movement of gradual translation in the direction of the axis of motion ; 
an effect which may be easily produced by a suitable adaptation of a 
sinrple or combination screw. It remains only to find the absolute value 
of the indications of the record, or the unit of value of the scale. For 
this purpose, when the machine is at rest, arms are attached to the shaft 



168 PARIS UNIVERSAL EXPOSITION. 

at right angles to the axis, and at points embracing between them the 
two points of application of the dynamoinetric apparatus, the two arms 
being in one horizontal plane and on opposite sides of the axis. From 
these arms are suspended scale-platforms which are loaded with weights 
gradually increasing, while the amount of torsion corresponding to each 
weight is directly observed. In deducing values for practical use in cal- 
culation, the weight of the arms and the attached scale-platforms must 
be considered and reduced to its equivalent supposed to be applied at the 
point of suspension. 

It is believed that this invention not only possesses the merit of entire 
originality, but that it is also a very important addition to the resources 
of the mechanical engineer. It has already been tested in many cases 
with results entirely satisfactory. 



CHAPTER VI. 
DIRECT APPLICATIONS OF FORCE. 

Machines for the elevation of water— Valve pumps— Earle's steam-pump — 
schabaver & foures's pump for the elevation of water, sand, and gravel — 
Perreaux's pumps — Antodymanic elevators — Champsaur's — Reynolds's WATER 
jet elevator — rotary pumps — centrifugal pumps — gwvnne & co.'s cen- 
trifugal pump — neut & dumont's— coignard & co's— cotgnard's helicoi- 
dal pump— Andrew's centrifugal pump— Gtrard's turbine elevator— Blow- 
ing machines — Lloyd's noiseless fan — Schiele's compound blowing fan — 
Evrard's rotary compression blower — Root's blower— Thirion's hydraulic 
pressure blowlr— Hydraulic presses— Challet-Champion's hydraulic press 
— Desgoffe and Ollivier's Sterhydraulic apparatus— Apparatus for test- 
ing THE TENSION OF WIRE — ASCENSEUR EdOUX — HYDRAULIC COUNTERPOISE — Gl- 
RARD'S PALIER GLISSANT — MECHANICAL PRESSES. 



I._HYDRAULIC ELEYATOKS. 

Tne number and variety of machines for the elevation of water present 
in the Exposition was very great. Every form of pump known had its 
representatives. The larger number of these were without originality of 
construction, though many of them were quite worthy of consideration 
for their cheapness or creditable workmanship. A few only have any 
particular claim to be noticed for novelty or improved efficiency. 

YALYE-PTJMPS. 
earle's steam-pump. 
An American steam-pump which, for its simplicity and steadiness of 

Fig. 40. 




Earle's Steam-pump. 



170 



PARIS UNIVERSAL EXPOSITION. 



action, attracted a great deal of attention, was exhibited by Messrs. G. 
D wight, jr. & Co., of Springfield, but was understood to be the invention 
of Mr. Oscar T. Earle, of the same place. This is a horizontal pump in 
which the pistons in the steam cylinder and water cylinder are attached 
to the same rod. The peculiar merit consists in such an arrangement of 
the steam valves as to produce a perfectly smooth movement, and to 
allow the pump to be started in any position of the piston. The valves, 
or apparatus for steam distribution, are contained in a cylinder imme- 
diately over the steam cylinder, and the movement of the slide is effected 
by means of an upright arm carried by the piston rod. The figure here 
given represents this arrangement. An air vessel immediately over the 
cylinder of the pump regulates the pressure of the ascending column. 
The necessity of a fly-wheel is obviated by the peculiarities of the steam 
distribution just mentioned, which could not be described intelligibly 
without the aid of sectional views. Access to the interior for the pur- 
pose of making repairs or adjustments is easy, and the small number of 
parts, the general simplicity of construction, and the compactness of the 
whole, are strong recommendations. 

SCHABAVFR & FOTJRES'S P03IPE CASTRAISE. 

A pump, called th.Q pompe castraise, exhibited by Messrs. Schabaver & 
Foures, of Castres, designed for elevating water containing sand or 
gravel, was distinguished by some remarkable peculiarities. A single 
cylinder is open both at top and bottom, and is traversed by a piston 
without a valve. The cylinder is enclosed in a larger vessel, water-tight, 
which is itself filled with water. This larger vessel is divided into two 
equal parts vertically, by a partition which joins the working cylinder, 
so that the cylinder itself forms a part of the division. One extremity 
of the cylinder communicates with the cavity on one side of the partition, 
and the other with the opposite. The valves are large ball.s of India- 
rubber, loaded in the interior with lead, and are kept in place simply by 

a kind of cage formed of curved straps 
of metal fixed over them. There are 
four valves. They are contained in 
separate boxes by the side of the prin- 
cipal box, and are in communication 
by pairs with the two cavities into 
which that box is divided. The figure 
given shows a section of the cylinder, 
and a view of the arrangement of the 
pair of valves corresponding to the 
nearer half of the cylinder reservoir. 
The piston is represented as at the 
bottom of the stroke. It is evident 

Schabaver and Foures's Pompe Castraise. that, when it rises, the lower valve 

must be raised by aspiration, and a volume of water will be admitted 
equal to the capacity of the cylinder. When the piston descends the 










K 


Jgsgggj^ 
















fag 


3 





EL 



HYDRAULIC ELEVATORS. 171 

lower valve will be closed by the pressure, while the upper one will rise 
and allow the water just admitted to be discharged. It is unnecessary 
to observe that the action of the second pair of valves corresponds to 
that of the first, as just described; so that the aspiration and the dis- 
charge are both proceeding, which ever way the piston maj be moving. 
What constitutes the special merit of this pump is, that the water which 
is raised enters only partially the box which contains the pump cylinder, 
and is immediately driven out again, without coming into contact with 
the piston itself 5 so that the danger of obstruction or injury by the 
introduction of foreign matters is small. The caoutchouc valves also 
adapt themselves under the pressure, easily to their places, notwith- 
standing that solid substances may sometimes be caught beneath them. 
This description of pump is therefore well adapted to the draining of 
marshes or of excavations where the waters bring along with them sand, 
leaves, or the debris of vegetation; but on account of its bulk and weight 
is not adapted to general use. 

Experiments made on this pump at the Conservatoire des Arts et 
Metiers, show an efficiency of fifty-six per cent, of the motive power, 
which is superior to that of most centrifugal pumps, and equal to that 
of other good piston pumps. At slow velocities, the performance 
reached sixty-six per cent. The waste of water by leakage was esti- 
mated at from seven to ten per cent. 

PERREAUX'S PUMPS. 

Certain pumps exhibited by Mr. Perreaux, of Paris, presented a pecu- 
liarity in the form of their valves, which is designed to adapt them to 
the uses for which the pompes castraises are intended. These valves are 
formed of India-rubber, cylindrical at the bottom, but having a quasi 
conical figure ending in a wedge-shaped summit. This wedge is split 
so as to form two lips easily opened by jjressure from beneath, but closed 
by pressure from above. It is easily seen that such a contrivance may 
serve effectually to prevent the return of water which has passed through 
it, even though foreign substances should occasionally lodge in the open- 
ing. A valve of this kind placed at the bottom of the cylinder, and 
another in the piston, suffice to form a lifting pump. 

AUTODY^AMIC ELEVATOBS. 

champsaur's autodynamic elevator. 

A simple and very ingenious water elevator was exposed by Mr. 
Ohampsaur, of Marseilles, which is capable of being made very useful 
where, as for instance for domestic purposes, it is desired to raise a lim- 
ited quantity of water per diem to a height of twenty or thirty feet. It is 
founded on the principle of the fountain of Heron, but is automatic in 
its action, and will continue to operate so long as the supply continues 
to be admitted from the source. Like the hydraulic ram, it elevates a 
portion only of the water which passes through it ; but it is much supe- 



172 



PARIS UNIVERSAL EXPOSITION. 



ft 



I 



rior to tlie ram in the amount of service rendered for a given expendi- 
ture. It is not, however, available in all situations, but requires that 
the waste water shall be discharged as far below the level of supply, as 
the portion to be utilized is to be raised above the same level. Wher- 
ever this condition can be secured, the contrivance cannot fail to be ser- 
viceable. 

Fig. 4-2. The operation of this machine can best be under- 

stood by reference to the accompanying figure, which 
represents it in section, and illustrates its principle 
without aiming to present the exact form. It is to be 
premised that the fountain of Heron consists essen- 
tially of two closed cavities at different levels, com- 
municating by a tube which opens into the top of 
each. When the fountain is ready for operation, the 
upper cavity is entirely full of water, while the lower 
contains only air. Water is then admitted into the 
lower cavity from a superior level, by means of a tube 
which descends to the bottom of that cavity, and 
which entering drives out the air through the tube 
of communication into the cavity or vessel above. 
This air entering above the water in that vessel, exerts 
a pressure upon its surface ; and if another tube be 
introduced, descending nearly to the bottom of the 
same vessel and open upwards, the water may be ele- 
vated through this tube to a height corresponding to 
the pressure exerted. 

In the figure referred to, the upper cavity or vessel 
is marked A, and the lower one B. The connecting 
tube is ps, interrupted in the drawing in order to bring 
the important parts near to each other. The cylinder 
C, which surmounts A, and the cylinder xy.z\ beneath 
B, are necessary to the automatic action to be now 
explained. 

Four floats, /, #, o, and n, are the principal means 
by which this automatic action is effected. The float 
g has a cylindrical opening through the middle, and 
it rests on «, which is a valve designed to close, at the 
proper time, the mouth of the tube »?, which is fixed 
amfc Elevator. yn " air-tight in the top of the vessel A. and is open at 
both ends. The float g is so adjusted in weight as to be just equal to 
an equal volume of water, so that when wholly immersed it tends 
neither to rise nor to fall. The float / is, however, buoyant in water. 
and it carries the valve a by means of a vertical rod or spindle. 

It being presumed that the whole apparatus is full of air. water 
is supposed to be admitted from the source through the pipe e. This 
water, falling into the vessel C, will descend through the tube m into 
A, which will gradually be filled, the air contained in it being expelled 




champsaur's autodynamic elevator. 173 

through the tube ps. A being filled, the vessel C will fill in its turn, 
aud the float / rising will close the valve a. The level of the water in 
C having reached K, there will be an overflow through the pipe Ki, 
and the vessel B will gradually fill. This vessel has also a valve in the 
bottom, marked ?, which is connected by a stem with the float o. The 
weight of this float keeps the valve closed so long as B contains only air, 
and when the water enters, its downward pressure on the valve contrib- 
utes also to maintain it in place. When the float is entirely immersed, 
it tends by its buoyancy to lift the valve; but its weight is so adjusted 
as to prevent any movement so long as the hydraulic head exceeds the 
height of the vessel A ; that is to say, so long as the tube Ki continues 
to be full. But as the water rises in B, the air is expelled through sp, 
and entering A, drives the water contained in that vessel upward 
through the ascending pipe rq. But it is obvious that the height of the 
point of delivery in rq cannot be greater than the height Ki, otherwise 
water would cease to flow through the tube K, and the supply would 
overflow the vessel 0, and run to waste. Practically, rq should be 
somewhat less in height than Ki Then supposing that the capacities of 
A and B are suitably adjusted to each other, the result will be that the 
level of the water in A will be depressed below the point r\ and the 
compressed air will escape through, rq. The pressure on the valve a 
being thus relieved, the weight of the float g will open the valve, and 
the water from C, entering again through m, will charge the vessel 
anew. 

But B is now full of water which must be discharged. The pressure 
of the hydraulic head having been taken off by the removal of the 
pressure in A, and the fall of the water level in C, the float o lifts the 
valve I and the water escapes. But I must be kept open until B is 
entirely empty ; and we have seen that the float o is heavy enough to 
close the valve unless it is entirely immersed, or nearly so. For this 
reason there are attached below B the two concentric cylinders xz and 
tu, the first and outer one having a discharge pipe ?/, and the second and 
inner having an opening v in the bottom which is insufficient to discharge 
the water as rapidly as it enters through the valve I. In this cylinder 
is placed a float n, attached to the same spindle which carries the valve 
I and the float 0, and which is sufficiently buoyant, while tu is full of 
water, to keep both raised. In the first efflux of water from B, tu is 
filled, and the overflow from it is discharged through y. After B is 
entirely freed from its charge, the water remaining in tu escapes through 
v, and the valve I is closed once more. The process then recommences 
from the beginning. 

The relative capacity of the vessels A and B will be determined by 
the height ISA and the height of the point of delivery in rq above r. If 
the point r is taken at the maximum height possible, then the elastic 
force of the air in A will be equal to one atmosphere, plus the pressure 
due to the hydraulic head Ki. Or, putting p for the natural pressure of 



174 PARIS UNIVERSAL EXPOSITION. 

the atmosphere, p' for the pressure in A, and h for the value of the 
hydraulic head, we shall have p ' =p + h. Assuming volumes to be 
inversely as pressures, as they will be nearly, since the heat developed 
by pressure will be principally absorbed by the water, then A should 
be to B, as p to p + h . 

If li be represented by the height in feet of A above B, or rather of 
the volume Ej', p may be taken as equal to 34. Suppose rq = 34 also ; 
and it would follow that B must be of twice the capacity of A. But if 
the height rq be less than the height Ki, it will be this height rq only 
which will determine the degree of compression to which the air in A 
will be subjected; and if we represent this height by h', we shall have. 

p'=p+h'; and A : B : :p :p + h'. 
Put then 

/^ = 17,anclA : B : : 34 : 51; 
Or A is two-thirds of B in respect of capacity. 

It is thus seen that the amount of water expended in proportion to 
the amount lifted is greater as the lift is higher. The case is not like 
that of a balance, in which a descending weight raises another equal 
weight through an equal space. There, no waste of power occurs except 
what is due to impediments to motion ; and hence the proportion between 
power expended and effect produced is the same whatever be the extent 
of the movement. The waste of force which occurs in this machine is 
that which is due to the compression of the air. Xo useful effect occurs 
until this compression is complete; but the water simply ascends in the 
pipe rq to a height increasing with the pressure. When the delivery 
commences, the pressure remains stationary ; the compressed air serv- 
ing merely as a medium for the transmission of force. Supposing h and 
li 1 equal therefore, the vessel B must be half filled with water before 
the useful effect begins. This measures the amount of waste. If h' is 
less than h, the delivery will commence when B is filled to an extent 
expressed by the fraction 

p+h>: 

If there are any uses to which the waste water can be applied at the 
lower level, it need not be a total loss. In a hotel, supposing that the 
water supply reaches only to the second or third story, this apparatus 
may elevate a sufficient amount for the service of the higher floors, while 
the waste water may supply a laundry in the basement. 

REYNOLDS'S WATER-JET ELEVATOR. 

Among the recently invented forms of apparatus for the elevation of 
water, is one which, though it was not present in the Exposition, is 
entitled to mention here for its novelty. This is the ingenious water-jet 
elevator, invented by Mr. Edward Reynolds, engineer of the Eiver Don 
Steel Works, at Sheffield, England, owned by Messrs. Tickers. Sons 
& Co. The power of a current of any fluid, liquid or gaseous, to drag 



reynolds's water- jet elevator. 175 

along with it the contiguous fluid through which it moves is well known. 
In Ewbank's Hydraulics, published thirty years ago, are described several 
forms of apparatus designed to produce exhaustion by the application 
of this principle. The practical application which Mr. Ewbank pro- 
posed to make of his inventions was to vacuum evaporation in the manu- 
facture of sugar. Supposing the sirup to be contained in a vessel having 
the form of a still with a retort neck reduced to a small diameter, he 
introduced into the neck through one side a steam-jet, which was bent, 
after entering, at right angles, and made concentric with the neck itself, 
leaving but a small annular space between the two. Steam under very 
high pressure being then blown out of the mouth of the tube, the air 
contained in the still is blown out along with it, and a vacuum is pro- 
duced which, as many of Mr. Ewbank's experiments proved, may 
become very nearly absolute. 

Mr. Reynolds's invention is substantially the same, except that instead 
of steam he employs a jet of water under high pressure, and utilizes the 
vacuum produced for the purpose of raising water from a well; or in the 
present instance from a pit which it is desired to drain. An ascending 
tube from the water of the pit, which may be called the tube of aspira- 
tion, is bent into a horizontal direction at the level at which it is desired 
to discharge the water elevated, and through the lower side of this tube 
is introduced the jet, which is also directed horizontally in the interior, 
and made concentric with the aspiring tube. The aspiring tube is two 
inches in diameter, but immediately in front of the jet it is reduced to 
three-quarters of an inch ; which reduced diameter is preserved for a 
length of three inches, after which the tube takes a flare and becomes, 
in a length of three or four inches more, of the original diameter again. 
The narrow part is called the barrel ; the enlarged part beyond, the 
delivery pipe. 

The diameter of the high-pressure pipe is one inch, but it is reduced at 
the jet to 0.15 inch, or about one-eighth of an inch. The jet is of brass ; 
the rest of the pump is of cast iron. The water is raised from a depth of 
fourteen feet, and though there is no foot valve, the pump primes and starts 
itself. One precaution only is necessary to secure this result, which is 
that the delivery pipe should not be so short and straight that the jet 
may pass out without meeting with some retardation by striking against 
its sides. In any case, however, if a momentary obstruction be placed 
at the mouth, say by merely placing the hand over it, the barrel fills, 
and then the operation goes on indefinitely. To fill the barrel is the 
only necessity, and this might be done, apparently, by a priming from a 
funnel above, if the simplicity of the expedient just mentioned did not 
render such a complication useless. The experiments thus far made 
show a delivery equal to seventy-two per cent, of that theoretically due 
to the full quantity of water expended. This ingenious contrivance is 
still the subject of experiment, for the purpose of determining the largest 
useful effect under various conditions. 



176 PARIS UNIVERSAL EXPOSITION. 

KOTARY PUMPS. 

It is generally true of rotary steam-engines that they are capable of 
being used as hydraulic engines also, by substituting the pressure of a 
column of water for thafHof steam. And as it is by the descent of the 
column that the machine becomes a motor, so if a more powerful antago- 
nist motor be employed to reverse the direction of revolution, it is obvious 
that the descending column will be forced to rise. Thus every rotary 
steam-engine is capable by reversal of being converted into a rotary 
pump. In fact this claim is distinctly made on behalf of all those which 
were exhibited in action in the Exposition, but only one of these was 
shown in operation as employed actually in the capacity of a water ele- 
vator. This was the engine of Behrens, exposed in the American 
department by Dart & Co., of New York. This machine and others of 
its class have been sufficiently described elsewhere. 

CEOTEIFUGAL PUMPS. 

Pumps called centrifugal are rotary also, but their efficacy depends 
upon a different principle. The action of the one is a lifting and that of 
the other a throwing action. In the former case, therefore, the return 
of the column is prevented by close packing ; in the latter by the supe- 
rior living force of the mass put into motion at its base. 

The invention of the centrifugal pump is ascribed to Appold, an En- 
glish engineer. It was first brought to public notice in London at the 
Exposition of 1851. All the forms which have since made their appear- 
ance have been only modifications in detail of the original model : but 
while these modifications have in some respects improved the construc- 
tion of the machine, or provided against causes liable occasionally to 
interfere with the regularity of its performance, they have not very 
sensibly improved its efficiency as measured by the relation between 
force expended and work done. A centrifugal pump may be compared 
to a ventilator receiving air at the centre and discharging it at the cir- 
cumference. Or perhaps a better illustration may be found in a turbine 
water wheel which receives a liquid column descending along a hollow 
vertical axis ; only that we must suppose the turbine in this case to be 
driven backward by another motor, so that the motion of the descend- 
ing column is forcibly reversed. Or if we suppose the turbine to be 
enclosed in a water-tight box, open only beneath at the centre, while a 
larger water-tight box includes this one, with an upright tube ascend- 
ing from it but not communicating with the water except through the 
interior of the turbine, then the turbine, being placed beneath the sur- 
face of the water and driven forward, will act as a centrifugal pump. 
The illustration first given is preferable, however, because it serves to 
show that the popular idea of this machine, derived from its name, is 
incorrect. The pump does not owe its efficiency to centrifugal force. 
any more than the ordinary compression or force pump does so. In the 



CENTRIFUGAL PUMPS. 



177 



first case supposed above, in which force is employed to drive a turbine 
backward, it is evident that a column may be made to ascend when 
the water pressure which lifts it is produced by a flow from the circum- 
ference toward the centre, but there would be no propriety in calling 
such a machine a centripetal pump. 

There is no doubt, however, that the inventor and most of his imita- 
tors have always regarded the elevating power of the pump as due to 
the rotary velocity given to the water in its interior. The theoretic 
investigation of its properties has therefore been invariably conducted 
on this supposition ; although experiment has made it manifest from the 
beginning, that the construction which that theory rigidly exacts as the 
condition of greatest efficiency, furnishes the most unsatisfactory results 
of all ; results, in fact, so unsatisfactory that if no better could be ob- 
tained, the machine would be economically a failure, and would have to 
be abandoned. 



GWYNNE & COYS CENTRIFUGAL PUMP. 

The general construction of the centrifugal pump may be understood 
by reference to the figures of the machine of Gwynne & Co., of London, 
(Figs. 43-46,) the first of which shows a section perpendicular to the axis 

Fig. 43. 



Fig. 44. 




Section through 
X Y. 



Gwynne & Co.'s Centrifugal Pump — scale, 1-12. 

of rotation, and the last, Fig. 46, another section along the axis itself. In 
a circular (but not cylindrical) box there are fixed six equidistant pallets, 
straight at first and coincident with the direction of the radii, but inclined 
toward their outward extremities. The water is received at the centre on 
12 i A 



178 



PARIS UNIVERSAL EXPOSITION. 



each side of the box, and is discharged through the circumference, and 
afterwards through the ascending tube L. The limits of the centre of 
admission are indicated in the figure. Only three of the pallets originate 
at the axis itself. The other three extend toward the centre as far only 
as the circle of admission. The figure showing the longitudinal section 
shows also that the pallets are sustained by lateral walls. This figure is 

strictly in section only 
where the shading is 
oblique ; the other 
shaded parts being 
beyond the surface of 
section. Thus, above 
and below the hub, 
through which the 
axis passes, are the 
open circles through 
which the water en- 
The pallets, as 
seen in the larger fig- 
are rounded 
edges within 
limit, in order 
that the influx may be 
as smooth as possible. 
The rotary apparatus 
is thus a box within 
a larger box, with 
which it is in contact 
only on two annular 
surfaces just at the 
circumference of the 
admission openings. 
The contact here must 
be as close as possible 
without serious Mo- 
tional resistance. The 
revolving drum, as 
observed above, is not 
cylindrical. As the 
water moves outward- 
ly from the central 
i 

^; opening with a ve- 

,' locity always increas- 

Gwynne & Co.'s Centrifugal Pump— scale. 1-12. ing, theory indicates 

that for a two-fold reason the breadth of each pallet parallel to the 
axis should diminish toward the circumference. For. first, if there 




GWYNNE & CO.'s CENTRIFUGAL PUMP. 



179 



were no acceleration of movement, the superficial area of each con- 
centric cylindrical section would have to be the same, which could 
only be made true by reducing its length in proportion to the increase of 
the radius j and in the second place, a proper provision for the real 
acceleration which is presumed to occur, would require an additional 
reduction. These are the indications of the centrifugal theory. Practi- 
cally it will be obvious on the merest inspection of any centrifugal pump 
that they are carried out only partially. In fact, there is no need for 
attention to the second particular, since it is not in the least desirable 
that the velocity of the water in a radial direction should be accelerated. 
On the other hand, the condition of greatest efficiency in this particular 
will be satisfied by giving such form to the rotating apparatus that the 
same volume of liquid shall pass through every concentric cylindric sec- 
tion in the same time, and that the radial velocity shall be constant. 

The general external appearance of the pump is shown in Fig. 45, 
where the form of the enclosing box is seen to correspond generally to 
the condition just stated, and where the position of the driving pulley 
on the axis of the rotary system is shown. Fig. 46 shows the system of 
pallets (shown in section in Fig. 44) in place, and also makes more clear 

Fig. 46. 




Gwynne & Co.'s Centrifugal Pump— section through the axis — scale, 1-12. 

the manner in which the water is admitted. H is the pipe through which 
the water arrives from this source ; H' and H" are sections of the two 
channels by which it is led to K and K", the central openings by which it 



180 PARIS UNIVERSAL EXPOSITION. 

enters the pump. One of the pallets appears at F. Between the rotary 
apparatus and the box which encloses it, is an annular space into which 
the water is driven by the motive power, and which is indicated in Fig. 
43. beyond the limits of the pallets at G-, and shown in section in Fig. 
46. At Y, Fig. 13, is further observed a partition which shuts off this 
annular space from the ascending tube L. At G is also indicated a 
small opening from the annular space behind the partition to the tube L, 
which is designed to allow any air which may accidentally find its way 
into the pump to make its escape. In case the pump were to be wholly 
immersed in the water of supply, the presence of air within the box 
would be a matter of no practical consequence ; but whenever, as will 
usually be the case, the water is to be raised to the apertures of admis- 
sion by the aspiration of the pump itself, it is easily seen that air in any 
quantity, in virtue of its elasticity, may diminish the power of aspira- 
tion, and finally destroy it altogether, precisely as the action of a siphon 
is arrested by the accumulation of air in the bend. 

Assuming the centrifugal theory to be the true one, the principles on 
which the efficacy of this machine depends may be stated as follows. 
By the rapid rotation of the pallets a similar rotation is imparted to the 
water enclosed within the box of the pump. If at any point of the cir- 
cumference of the box a tangential tube, of no greater cross-section than 
the annular cavity G, should be attached, communicating with the inte- 
rior, but not prolonged externally beyond what is necessary to clear the 
circular contour of the box, a stream would gush from it having the 
same velocity as that belonging at the moment to the water in the annu- 
lar cavity. If now we suppose the tube to be prolonged upward and to 
receive successively different lengths, we shall find that while the height 
is small the water still flows with considerable velocity, but with a 
velocity diminishing as the height is increased. 

At considerable heights the quantity of water delivered in a given time 
will become very small, and by careful trials we shall at length find a 
height at which (supposing the machine to be driven uniformly) the tube 
will stand permanently exactly full, but will deliver no water at all. 
Xow, at any stage in the course of these experiments, by opening a stop- 
cock at the bottom of the column we shall find the velocity of efflux at 
that point entirely unchanged, and this velocity will be the same as is 
observed when no column is raised at all. Moreover, if after the water 
attains its maximum height and comes to a stand-still in the tube, we 
cut off communication with the pump, and by opening a stop-cock in 
the foot of the tube ascertain the velocity of the water issuing under the 
pressure of the column, we shall find it exactly what it was found to be 
while the communication with the pump was free. Xow. it is a familiar 
truth in hydrodynamics that the velocity with which a liquid issues from 
an orifice in the containing vessel, in virtue of its own pressure, is 
exactly equal to that which a heavy body would acquire in falling freely 
from the level of the surface of the liquid to the level of the orifice of 



CENTRIFUGAL PUMPS. 181 

escape. If then the height is given, the velocity may be found ; and 

if the velocity is given, the height may be found. Patting h for the 

height, v for the velocity, and g for the force of gravity represented by 

the velocity which this force will impart to a falling body in one second 

from rest, (32.083 feet,) it is true that — 

v 2 
v 2 =2gh', or h=j. 

To find h, the maximum height to which the pump may be presumed 
capable of raising a column, we want only therefore to ascertain the 
value of v, the velocity imparted to the fluid in the annular space G, 
when'the number of revolutions per minute of the axis of the pump is 
known. What this velocity in given conditions ever actually is, could 
probably only be ascertained experimentally in the manner suggested 
above. But it is sufficiently evident that there is a limit which it cannot 
exceed, and that is the velocity of the outermost extremities of the pallets 
from which it receives its motion. This velocity may easily be computed 
when the number of revolutions and the distance of the extremity of the 
pallet from the centre of motion are known. Put n, for example, for the 
number of revolutions per minute, and r for the radius of the circle 
described by the pallet, and we shall have the space moved over per 
second, or the velocity sought, in the expression 

27tm 7tm 

V 60 30"' 

And 7i=^ = 5^ 2 = 0.0001705475r% 2 . 
2g 1800g 

Mr. Appold, the inventor of the machine, gives as the formula for the 

velocity at the circumference, for the height, H, in feet, per minute, 

y^SSO + SSO^/H, 

or in feet per second, 

y^oi + oiVH. 

We can compare this with the requisitions of theory by finding the 
value of H, 

H=_ J « 

9f 

and putting this equal to the value of h, as given above, we shall then 
have 



> 



V=9£+V:£-X0=9| + 1.143t\ 

It would thus appear that the practical velocity exceeds the theoretic 
about one-seventh, increased by a constant slightly exceeding nine 
feet ; but this inference does not accord with the fact that the actual 
performance of Mr. Appold's own pump, as tested at the Conservatoire 
des Arts et Metiers, gave, on an average, hardly more than one-half the 
theoretic result, and was more deficient as the velocity was increased. 

There is another mode of regarding the centrifugal theory which would 



182 PARIS UNIVERSAL EXPOSITION. 

lead to a somewhat different expression for the power of the machine. 
The water entering at the central opening and passing out at the circum- 
ference, may be considered as acted upon throughout its movement in 
the radial direction by a continuously acting but increasing force, which, 
if v' stand for the angular velocity and r for the variable radius, may be 
expressed by rv' 2 . 

And by substituting for v' its value deduced from the velocity v in the 
circle in feet as itself derived from the number of revolutions per minute 
and the length of the radius, we shall have, for the value of the accel- 
erating force — 

- 2 n 2 r 

And if we take V to express the radial velocity generated while a 
given particle of water is passing from the point of entrance (say at the 
distance r" from the axis) to the distance r', or the extremity of the 
pallet, we obtain by the ordinary process in such cases 

V 2 = ~ n (r 12 r" 2 \ 

900 l h 

This velocity is imparted to a mass m, which has passed from r" to r'; 
and 

the work performed = mY 2 = m ~^ 2r \ y' 2 —r in ). 
Or if w stand for the weight of the mass, 

*=*, andmV-^V-'"' 2 ); ancl^-(,--,-, 

expresses the height to which the mass may be raised. As every other 
mass passing through the pump is acted on in like manner, all the water 
which passes will be carried to the same height ; but when the force of 
gravity on the column raised is sufficient to balance the accelerating 
force, the movement will be arrested. 

This expression differs from the former in containing (r n — r"' 2 ) in place 
of r 2 simply. The two would become identical if the water were supposed 
to enter the pump precisely in the centre of rotation. 

If the theory which ascribes the ascent of the column wholly to cen- 
trifugal force were correct, it would follow that the form of the pallets 
which most effectually impresses upon the fluid in the pump a rotary 
motion, would produce the best result ; and hence that the construction 
originally employed, in which the pallets were without curvature and 
were placed in the direction of the radii, would be preferable to any 
other; but in point of fact this construction of the machine was found 
experimentally to be inferior to that subsequently adopted, and which 
is illustrated in the pumps of Messrs. Gwynne, Figs. 43-46, and of Feat 
& Dumont, Figs. 47, 48, in the ratio of two or three to one. It will be 
seen, indeed, by reference to the first of these figures, that the water in 
the annular space, G-, cannot have a rotary motion in the upper part of 



CENTRIFUGAL PUMPS —NEUT & DUMONT's. 183 

the ring, in consequence of the interposition of the partition at the point 
G. The mechanical action which does really take place is one of com- 
pression exerted by the inclined surfaces of the pallets, by which the 
water is forced into this space laterally, so that the circular column, 
abutting against the partition, is compelled to find exit in the direction L. 
This effect is independent of any rotary motion of the water, and indeed 
could not occur at all were the water to be animated by the same angular 
motion as the pallets. It is true that, in so far as the liquid is really 
thrown into rotation, centrifugal force comes into play and contributes 
its part to the result $ but it is evident that the compressing action is 
the most advantageous, so that the puinp in which the motion of the 
water is to the greatest extent radial, and least circular, will perform 
best. The case is analogous to that of a turbine receiving water at the 
centre, in which the greatest efficiency will be realized when the water 
leaves the wheel most nearly in the direction of the radii. 

If we suppose that by the direct action of the pallets in impressing a 
radial velocity upon the water in the pump, and by the indirect effect of 
the rotary motion combined, a given elementary mass is forced from the 
centre to the circumference during a certain fraction of the revolution, 
as, for instance, one-eighth, we shall be able to compute the velocity with 
which the liquid would issue from a tube placed tangentially as L, and 
having the same cross-section as G ; this section being supposed to be 
equal to the total cylindrical area of discharge from the rotating drum. 
Let the pallets measure nine inches from the point of admission of the 
water to the circumference of discharge, in the direction of the radius, 
and let the number of revolutions per minute be 900, we shall then have 

^=900 x f X 8 x gV^ 90 feet ? 
which is very nearly the velocity found theoretically by the former 
method of computation. 

NEUT & DUMONT'S CENTRIFUGAL PUMP. 

The pump of Messrs. Neut & Dumont, Figs. 47, 48, differs from that of 
Mr. Gwynne in the details of its construction. The pallets are more 
regularly curved, and are twelve in number, four only extending to the 
centre. The supply is admitted through a horizontal tube which conducts 
to both surfaces, as seen in the horizontal section, Fig. 48. The rotating 
drum is reduced to smaller dimensions at the circumference of discharge. 
This machine is also furnished with an ingenious contrivance, not shown 
in the figure, for preventing the entrance of air into the interior through 
the stuffing boxes of the driving shaft. These stuffing boxes are double, 
or are divided into two compartments 011 the axis, between which there 
is a water-tight annulus which communicates by a tube with the rising 
column of water. If, in consequence of imperfect packing or any irreg- 
ularity of movement, air should be drawn in through the joints of the 
outer stuffing box, it makes its escape upward through this communi- 
cating tube ) and if the joint of the interior stuffing box should work 



184 



PARIS UNIVERSAL EXPOSITION. 



loose, the only consequence which would follow would be the introduction 
of a small quantity of water into the pump, but no air. 

Fig. 47. 




Neut & Dumont's Centrifugal Pump— vertical section. 

The tunnel seen in the vertical section, surmounting the pump, is 
designed to fill it with water before the commencement of motion. There 

Fig. 48. 




Neut & Dumont's Centrifugal Pump — horizontal section. 

is, of course, presumed to be a valve at the bottom of the tube of aspira" 
lion, opening upward. 



CENTRIFUGAL PUMPS — COIGN ARD & CO. S. 



185 



COIGNARD & CO.'S CENTRIFUGAL PUMP. 

In the pump of Messrs. Ooignard & Co., of Paris, there is a much 
larger departure from the ori- Fig. 49. 

ginal model. A vertical sec- 
tion across the axis of one of 
these pumps is shown in Fig. 
49, and another section, also 
vertical, through the axis, in 
Fig. 50. Here, there are two 
revolving drums G A G, both 
attached to the same axis D. 
They revolve, as before, in 
water-tight boxes, but the en 
trance of the water takes place 
from the space O I, between 
the drums; the openings for 
admission being at F. The 
discharge takes place through an annular lateral space e e e e, into an 
annular cavity M M, which conducts it to the rising tube K The tube 

Fig. 50. . 





Coignard & Co.'s Pump — section. 

of aspiration is L, which communicates with the space between the 
drums O I. The form given to the pallets in this machine is spiral; they 
are only two in number in each drum. As in the other pumps, the 
form of the helices is professedly such as to make the section of passage 
inversely proportional to the velocity of the water at different distances 
from the centre. 

The obvious advantages of Mr. Coignard's construction are, the pre- 
vention of the loss of living force in the column of aspiration which 
occurs in other pumps by the encounter of two currents entering from 



186 PARIS UNIVERSAL EXPOSITION. 

opposite sides, and the freedom from liability to receive air mingled with 
water in aspiration, since such air rises to the middle of the space be- 
tween the drums, above the openings F F, where provision is made for 
its escape. It has, moreover, stuffing-boxes only on one side. The term 
ftelicoidal, applied to this pump by the inventor, describes the form of 
the pallets, and indicates that he recognizes the action of the machine 
to be one of compression as well as of projection. \Ye find no record of 
any experimental trials of the pumps of Mr. Coignard : but it is stated 
that the proportion of useful work done by them amounts to sixty-live 
per cent, of the force expended. In the use of the pumps of Gwynne, 
and of Xeut & Dumont, as well as of those of Mr. Appold, (not on exhi- 
bition,) the results of experiment show this proportion to be, for the 
first, forty-five per cent, ; for the second, fifty-seven ; and for the third, 
about sixty. These numbers give the superiority to Mr. Coignard over 
all the rest. It is to be taken into account, also, that the number of 
turns per minute in the experiments with Mr. Appold's punip averaged 
eight hundred, and in Xeut & Dumont's only five hundred. In the case 
of Gwynne's pump, the average number was six hundred and forty. It 
is, of course, to be desired that the number of revolutions shall be kept 
as low as possible consistently with the attainment of the object. 

Some of the pumps exhibited by Coignard & Co. were very powerful. 
One of them, in operation in the park, poured out a real cataract in the 
form of a sheet of water twenty or thirty feet wide, fifteen feet high, 
and several inches deep. Another, at the island of Billancourt, raised 
water by aspiration from a depth of over twenty-six feet and elevated it 
more than fifty- two feet further, being a total height of about seventy- 
nine feet. Mr. Coignard claims that these effects are produced with a 
velocity of rotation less than that required in other centrifugal pumps. 

The centrifugal pump is capable of useful applications to which no 
other machine for elevating water yet invented would be equal. It 
throws out so vast a volume of water in limited time that it may be used 
to drain marshes, to supply water for canals, to draw the water from 
coffer-dams, from dry-docks, &c, and to pump out foundered vessels. 
For this last purpose a pump of Coignard & Co. was employed on the 
occasion of the sinking of the Florida in the harbor of Havre. The vessel 
was raised without difficulty, when, without the aid of this powerful 
machine, she must have been abandoned. 

The fact that the helieoidal pump of Coignard, & Co.. at Billancourt. 
was competent to raise a column of water eigty feet, and this, as specially 
claimed by them, a vitesse reduite, furnishes increased evidence of the 
truth of the opinion expressed above, that the action of this machine is 
an effect more of a compressing than of a centrifugal force. On the cen- 
trifugal theory the maximum height to which a pump of nine inches 
radius (the size of that employed in the test experiments on the pump 
of Mr. Gwynne, at the Conservatoire des Arts et Metiers,) could elevate a 
column of water, with a velocity of five hundred turns per minute, would 



CENTRIFUGAL PUMPS ANDREWS S. 



187 



be only twenty-four feet ; and by increasing the radius to one foot, tlie 
height would be increased only to forty-two and a half feet. In order 
that the column might rise to eighty feet, the number of revolutions 
would require to be increased on the first supposition to upward of 
nine hundred, and on the second to six hundred and eighty. These 
numbers by no means represent a vitesse redtiite ; and the calculations 
from which they are derived make no allowance for the inevitable loss 
of force which occurs in practice. These numbers, moreover, indicate 
what is required to produce a maximum elevation to eighty feet, at which 
height, of course, no water could be delivered. If the compression theory 
is true, the height does not depend on the rotary velocity generated in 
the water, but on the radial velocity, which may be greater than that 
wmich would result from the effect of rotation. 

A further confirmation of this view is drawn from the fact that in cer- 
tain of the pumps of the Coignard & Co., the two drums are made to act 
consecutively upon the same water : that is to say, the water is aspired 
by one of them only, and is passed from that one to the other, preserving 
the velocity already acquired, and receiving a new velocity in the second. 
This is probably the construction of the punrp at Billancourt. The effect 
is to raise the column to a greater height than could be accomplished by 
using both drums simultaneously on different volumes in the ordinary 
way ; but evidently the ultimate velocity is greater than that which is 
due to the centrifugal force of revolution, and the height is experiment- 
ally greater than the limit which the centrifugal theory would impose. 

ANDREWS'S CENTRIFUGAL PUMP. 

The centrifugal pump exhibited by Messrs. W. D. Andrews & Bro., 

Fig. 52. 




Andrews's Centrifugal Pump. 



188 



PAEIS USTVEESAL EXPOSITION 



of Sew York, is a still wider departure from the original model of Ap- 
pold than that of Mr. CoignanL As shown in the annexed figure, which 
is reduced from the designs published in the London Engineering, 
in May, it has. in one view, an appearance somewhat resembling a helix. 
or snail's shell. This helix forms the base of a double cone placed with 
its axis in a horizontal position, the space between the inner and outer 
cones being the chamber of the pump, and being occupied by a kind of 
turbine wheel. 

Fig. 52 is a vertical section : Fig. 53. the rotating disk, and propelling 
wing- : Fig. "4. the stationary boss and spiral flanges. A is the base of 
the pump, cast in one piece with the case 0, and strengthened by brack- 
ets, a a a a. To the chamber C is attached by flanges l> l>\ the con- 
ducting case, composed of two parts. D D . united by flanges, ~ <~ . and 
forming a spiral discharge passage g and E. commencing ate. and grad- 
ually enlarging to the outlet e. F is the sttirhng box. through which 
passes the cast steel driving shaft G this having turned in its surface. 

at -T. a series of grooves which are accurately 
tltted in a Babbitt metal box in the standard 
H and its cap }>.. counteracting all tendency to 
end-thrust or vibration. I is the bed-plate, 
having cast upon it the standard FT. and brack- 
ets, to which the pump is secured by the flan _ e - 
d d . and base A. When required to be run 
vertically, no bed-plate is used, but the pump 
is secured by the base A. The base A also 
forms a hange. to which is bolted the bend Q 
with the suction pipe B attached, shown bro- 
ken otf. this pipe having a foot valve at its 
lower end. 

To the tLange /. on the discharge orifice, are 
attached pipes for conveying the water where- 
ever required. In Fig. 52 K is the disk secured upon shaft G. bar- 
ing wings. 1. 2, 8. 4. 5, 6 set- Fig. 53 upon its periphery, closely 
fitting the space between it and chamber C. within which they 
revolve without touching. Their discharge ends extend beyond K. 
cl >se to the case D . without touching it. and terminate on a line par- 
allel t<> the shaft G, L is the boss connected by flanges J 1 I J - 
F:_. 5i. to the chamber O, forming spiral induction passages. In the 
end of shaft G. is a steel button a. with a convex face, which revolves 
in contact wirh the convex end of the step X. secured in the boss L. 
supporting the shaft and disc when run vertically. Motion is commu- 
nicated t< :• the disc by a belt upon the pulley P. The pump and pipes 
first being tilled with water, rapid motion is uiven to the disc K. when 
the centrifugal force imparted to the water between the wings causes it 
t:» flow through the passages § and E. to the outlet e: a vacuum being 
thereby created between the wings, which causes the water to rise 
through the pipe B. to keep up the supply. 




CENTRIFUGAL PUMPS TURBINE ELEVATOR. 189 

By means of the spiral passages around the boss L, the water from 
the suction-pipe is turned gradually from a direct forward course, and 
delivered to the propelling wings in the line of their action $ thence, 
through the spiral passages g and E it is again, by an easy, gradual 
curve, brought back to a straight course, upon reaching outlet e. The 
wings on the disc K, passing beyond its outer edge, create and main- 
tain a vacuum between it and case D, and prevent sand, dirt, &c, from 
coming into contact with the shaft. The bearing UST is in like manner 
protected from dirt, enabling the pump constantly to discharge a large 
proportion of sand, gravel, &c, without injury to any of its parts. There 
being no valves in action, (the foot valve remaining open while the pump 
is in motion, and used only to retain the charge when at rest,) and no 
wearing parts except the shaft in its bearings, which is perfectly pro- 
tected from dirt, the friction is much reduced, enabling the pump to run 
for a considerable time without repairs. 

The pump, as exhibited in the Exposition, raised a large volume of 
water from a tank, and discharged it through a broad flat spout into the 
same tank again. No data were obtained by which to compare its per- 
formance with that of any of the other engines of its class ; but its con- 
struction is evidently favorable in a high degree to efficiency. Of the 
other pumps, that of Coignard & Co., seemed to perform best ; but it 
forces the water, at the points G, e, and M, (see Fig. 50) to make an 
abrupt turn, which cannot but diminish the useful effect, while in the 
pump of the Messrs. Andrews all the curves are easy, and the helix 
gradually enlarges up to its junction with the delivery pipe in a manner 
to accommodate itself most advantageously to the necessary changes of 
velocity. Apparently this is a very superior elevator. 

(HRARD 7 S TURBINE ELEVATOR. 

A more extended application of the principle of the centrifugal pump 
has been made by Mr. Girard, of Paris, in a machine called by him a 
turbine elevator. It is in fact something like an ordinary turbine 
revolving on a vertical axis, but having five distinct turbine wheels one 
above another on the same axis. A reference to the figure will make the 
construction intelligible. The water enters through the tube A, and is 
acted on by the pallets 0, of the first turbine. Thence it returns to the 
centre through the space D, and enters the second turbine through E. 
Passing through all the turbines successively, it is finally discharged 
through the pipe E, which leaves the turbine horizontally, but is designed 
to be connected by a curve with an ascending tube. At the axis, where 
the water passes from level to level, it is guided by thirty-six curved 
plates, so fixed as to give it a direction most suited to enter the chan- 
nels in the turbine wheel between the pallets. Fig. 56 shows at B the 
position of these guides ; and the same figure shows the form of the 
pallets. These are twelve in number ; the water as it enters taking a 
direction nearly radial until it approaches the circumference, when it is 



100 



PARIS UNIVERSAL EXPOSITION. 



exposed to the action of the inclined front of the pallet. In his first 
machine, the angles in these water passages were more abrupt, and the 
Fig. 55. inclination of their out- 

er faces to the circum- 
ference was less. The 
slight alteration in- 
creased the useful ef- 
fect by one-third. It is 
probable that a greater 
alteration in the same 
direction would in- 
crease it still more. 

The idea of making 
centrifugal force avail- 
able for the elevation 
of water is not a very 
new one : but it is only 
recently that a machine 
truly useful has been 
constructed on this 
principle. Gen. Morin, 
in his treatise on hy- 
draulic machines, men- 
tions as the earliest in- 
vention of this kind the 
pump of LeDemours, 
which consisted simply 
~ of an inclined tube firm- 
ly attached to a verti- 

Girard's Turbine Elevator. Cal axis, with which it 

revolved. The centrifugal force generated by the revolution caused the 
water to rise; and the tube being bent outward and downward at the top, 

delivered it into a circular trough. This 
^ same thing in principle was reproduced in 
v 1855, at the exposition of that year in 
Paris, by Mr. Piatti, whose invention con- 
sisted of hollow and concentric cones sur- 
rounding and fixed to an axis of revolu- 
tion. The water was made by the revo- 
lution of the system to rise between the 
cones, and was delivered in like manner 
at the top into a circular trough. One or 
two partitions dividing the conical annu- 
lar space in which the water was raised. 
N prevented the sliding of the liquid upon 

the solid surface, and forced it to take the gyratory motion of the con- 
taining vessel. This machine may be made a means of raising large 




Fig;. 56. 




CENTRIFUGAL PUMPS — BLOWING MACHINES. 



191 



volumes of water; but the useful effect, as shown by experiments on Mr. 
Piatti's machine, does not exceed one-fifth of the power expended. 

In 1850, or about that date, a centrifugal machine was exhibited in 
New York, which was claimed to be a realization of the perpetual 
motion. Instead of the two hollow cones of Mr. Piatti, it was proposed 
by the inventor of this machine to substitute a vessel in form somewhat 
resembling a soup plate, covered by a lid secured at the centre, but rest- 
ing loosely at its circumference on the rim of the plate. From the 
centre of the plate beneath descended a tube, which was also the axis 
of revolution. This tube contained likewise a spiral like that of the 
Archimedean water-screw. The lower extremity was to be placed in a 
liquid ; and the whole interior being filled with the same liquid, for which 
purpose a valve opening upward was placed at the bottom, the whole 
was to be set into rotary motion. It was presumed that the liquid, 
escaping by centrifugal force from the perimeter of the vessel at the top, 
would act by aspiration on the liquid in the column and in the vessel 
beneath, producing an upward current, which, acting in turn on the 
spiral, would exert force enough to maintain the revolution, with also a 
surplus outstanding to be applied to other purposes. The liquid dis- 
charged from the vessel at the top being returned immediately to that 
at the base of the column, provided for the permanent maintenance of 
the motion. Inasmuch as a liquid of so little density as water could not 
be expected to furnish a large amount of surplus power, it was proposed 
to substitute mercury ; and inasmuch as mercury, under atmospheric 
pressure, cannot be raised by aspiration more than thirty inches, it was 
further proposed to enclose the whole apparatus in a strong air-tight 
box, and to condense the air within it to the extent of many atmo- 
spheres. Surprising as it may now seem, this extraordinary theory found 
many defenders, and was made the subject of a protracted discussion in 
the public journals, in which some gentlemen having a scientific reputa- 
tion participated. 

II.— BLOWING MACHINES. 

LLOYD'S NOISELESS FAN. 

A variety of ventilators or blow- 
ing machines were present in the 
Exposition, of which a number 
were constructed substantially on 
the same principle as the centrifu- 
gal pumps. One of these is repre- 
sented in the accompanying fig- 
ures, the first of which shows only 
the external box enclosing the ma- 
chine. The ventilator itself, which 
is partially seen in Fig. 58, consists 
of a drum formed of two flat hollow 
cones of thin metal, brought near 
together by their bases, and con- 




192 



PARIS UNIVERSAL EXPOSITION. 



nected by a series of curved partitions extending from the centre to 
the circumference. The cones are open about the vertices, and an axis 
of revolution supports the whole by being the common origin of all the 
curved partitions. This drum rotates within a closed box, and discharges 
the air received at the centre through a tangential outlet. The details 



Fiff. 58. 



of internal construction too closely 
resemble those of Appold's pump to 
render further explanation necessa- 
ry. The figures represent the u Xoise- 
less Fan*' of Mr. George Lloyd, of 
London. Its recommendations are 
the silence with which it works and 
the volume of air which it delivers. 
Mr. Lloyd constructs a number of 
models varying in size from thirteen 
inches to four feet in diameter. The 
smallest are driven with the velocity 
of eighteen hundred or two thou- 
sand feet per minute, and the larg- 
Liovd's Noiseless Fan. est eight hundred or one thousand. 

As furnace blowers, the smallest will melt six hundred- weight of iron in 
one hour, and the largest one hundred and twenty hundred-weight. 
As an exhauster of foul air in mines, this machine is used without the 
surrounding box. The tube of aspiration being connected with the cen- 
tre of the drum, the air drawn up is discharged from the circumference 
into the atmosphere. 




schiele's co^lpoend blowing fan. 



Blowing machines of similar character were exhibited by the North 
Moor Foundry Co., of Oldham, England, being the inventions of Messrs. 
Piatt and Schiele. A remarkable one among these was called the Com- 
pound Fan, designed for high-pressure blasts. In this, two fans, re- 
sembling in general the fan of Lloyd above described, were combined on 
the same shaft, so as to act successively on the same air. By the first 
the air is driven into a chamber between the fans, at a pressure of per- 
haps six ounces. The second receives the air at this pressure and com- 
presses it at much more, so that it is delivered at length into the fur- 
nace at a pressure of twelve ounces per square inch. The advantages of 
these fans for reverberating furnaces are stated to be — 

First. Great saving in fuel, the consumption being less for a given 
effect in proportion as the pressure of the blast is increased. 

Second. Seduction of the time required for melting. 

Third. A more thorough liquefaction of the metal. 

Hitherto, it is stated, the highest pressure attainable by tans of any 
description has been only about six, or at most seven, ounces per square 



BLOWING MACHINES. 193 

inch. The improvement is, therefore, an important one. A ventilator on 
this same principle, constructed by Mr. Perrigault, was one of those em- 
ployed in the ventilation of the palace of the Champ de Mars ; whether 
claimed as an original French invention or not was not ascertained. 

EVRARD'S ROTARY COMPRESSION BLOWER. 

One or two rotary ventilators on the compression principle deserve a 
brief mention. Of these, one, which was exhibited by Mr. Evrard, of 
Mons, was a literal application to the compression of air, of the prin- 
ciple of the rotary steam-engine of Breval, described in another part of 
this report. The figure of that engine may be referred to, and will, in 
fact, serve perfectly to illustrate the construction of this machine. Two 
cylinders, whose radii are as two to one, and whose lengths are equal, 
revolve in contact, rolling one on the other, except where a cycloidal 
indent in the smaller receives a projection or pallet on the larger. In 
Breval's engine there are two pallets diametrically opposite to each 
other on the larger cylinder, and one indent in the smaller. In this 
machine there are four pallets attached to the larger, while the smaller 
has two indents. It will be easily seen that this multiplication of parts 
does not increase in the least the volume of air delivered, but does 
increase the amount of dead space, and the chances of leakage. 

root's compression rotary blower. 

Another ventilator by compression, which was noticed with much 
favor, was exhibited by Mr. P. H. Boots, of Oonnersville, Indiana. This 
may be understood by supposing the rotary steam-engine of Pillner and 
Hills to be so modified in construction that the two toothed wheels 
which form the interior moving parts of that engine are replaced by 
two bodies having each a contour something like a leumiscate curve, or 
figure 8. This is substantially to replace wheels with numerous small 
teeth by others having each but two exceedingly large teeth. These 
revolve in pretty close contact, within a box to which they are fitted, so 
as to run as close as possible without friction. The wings being about 
two feet long, with a considerable length of axis, this machine is 
capable of delivering a large volume of air with a moderate velocity of 
rotation. Driven at the rate of two hundred and fifty turns per minute, 
it was stated to produce a pressure equal to one-third of an atmosphere, 
or five pounds per square inch. 

thirion's hydraulic pressure blower. 

Still a third compression ventilator appeared in the Exposition, which, 

for its simplicity and its originality, seems to merit notice. It is called 

by the exhibitor, Mr. Thirion, of Mirecourt, France, a machine soufflante 

a colonne cVeau, but the water referred to in the name served no other 

13 I A 



194 



PARIS UNIVERSAL EXPOSITION. 



purpose but to pack the moving parts and prevent friction, 
annexed will serve to render the construction intelligible. 

Fig. 59. 



The figure 




Thirion's Hydraulic Pressure Blower. 

Three cylinders are here seen, side by side. The two lateral ones are 
the compressors, and the middle one the regulator. One of the com- 
pressors is shown in section. A is a cylinder of wood or sheet metal, 
as may be convenient, bolted to the base which sustains the whole. 
Within this is another cylinder, and between the two is an annular 
space which may be filled to any level desired with water. The water 
level in the figure is shown at O. Between these two cylinders is sus- 
pended an inverted cylinder, or cylinder open downward but closed at 
top, which enters the annular space between the two cylinders first 
named, without touching either. In the top of this suspended cylinder 
are two valves, E and E, which open inward. A cap is placed on the 
central cylinder within, and in a valve-box beneath this are two other 
valves, F and F, which open outward as shown. From the closed space 



thirion's hydraulic pressure blower. 195 

into which these valves open, descends a pipe D, which communicates 
beneath the base by means of the recurved and rising- tube H, with the 
regulator. The action of the machine will now be easily understood, it 
being observed that the regulator is constructed on the plan of the com- 
pressor so far as that the cylinder B, which is closed above and open 
below, descends into an annular space containing water, like the sus- 
pended cylinder of the compressor. The cylinder B, however, is not 
suspended, but is simply kept in an upright position by a guiding rod 
proceeding from the centre of its crown. It has also a scale pan above 
it to receive pressure weights, and should have a safety valve, though 
none is shown in the figure. The movable cylinder of the compressor 
is suspended from a crank or eccentric on the driving shaft of a prime 
mover. As in the revolution of the shaft the cylinder is lifted, air enters 
by the valves E, which spontaneously open. As the cylinder descends 
the valves E close, and the valves F are opened by the pressure of the 
contained air which is condensed by the force of the motor. The con- 
densed air then finds an escape through D, and enters the regulator 
through H. At the top of H is a valve which is represented as raised 
by the entering currents. The cylinder B rises to give room for the 
entering air, the pressure remaining constant and being dependent on 
the weight with which the scale pan is loaded. The second compressor 
acts alternately with the first 5 so that a stream of air is constantly 
entering the reservoir from one or the other. A tube P, from the centre 
of the regulator, descending below the base, conducts the blast to the 
point where it is needed, and where it is delivered through a tuyere P. 
A siphon gauge attached to this tuyere shows the pressure of the air 
at the efflux. Of course, as the pressure is increased, the level of the 
water within and without the movable cylinders, both of the compressors 
and of the regulator, will become unequal ; and the maximum pressure 
attainable will be only equal to the vertical height between the top of 
the fixed cylinder A and the bottom of the movable cylinder when at 
its highest point. If the water in A is in too great quantity to admit 
of such a pressure, it will run over until the pressure is attained. If it 
is in deficiency the maximum cannot be attained, but the air at some 
pressure interior to the maximum will begin to escape from beneath the 
bell. These statements are founded on the supposition that the sus- 
pended cylinder, or bell, divides the annular space into which it enters 
equally. Greater pressure may be obtained by the use of a liquid 
heavier than water ; and, for powerful blasts, Mr. Thirion proposes to 
employ mercury. With water he obtains a pressure of ninety-five centime- 
tres, (about three feet,) or say a pound and a half to the square inch. Sub- 
stituting mercury there might be obtained, with half the difference of 
level, two-thirds of an atmosphere. The pressure of a pound and a half, 
however, is about four times that which is furnished by a good venti- 
lating fan, and higher than is- commonly used in cupola furnaces. 

This machine has four very decided recommendations. It works 



196 PARIS UNIVERSAL EXPOSITION. 

almost without friction or leakage; the deterioration by wear is inap- 
preciable; the perfect and exact regulation of the pressure is easy; and 
finally, the excellence of its performance depends in no degree upon 
precision of workmanship. It is a machine, therefore, which is espe- 
cially adapted to the exigencies of furnaces in new countries and among 
the mountains, since it can be easily constructed on the spot, and will 
give no trouble in consequence of derangements. 

IIL—HYDBAITLIC PBESSES. 

In the construction of the hydraulic presses exhibited, the ingenuity 
of inventors has been chiefly exercised in contriving expedients to accel- 
erate the application of the power. One of the most obvious of these is 
to accumulate a large volume of water in a reservoir under a pressure 
equal to the maximum which it is desired that the press shall exert, and 
to open communication between the press and the reservoir by means of 
some form of stop-cock. If the pressure is to be exerted only through 
a small space, no other provision is necessary ; but if the course of the 
piston is considerable, and the resistance extreme only toward the close 
of the movement, water may be thrown in rapidly by forcing pumps of 
large capacity, or introduced from a reservior under less pressure, until 
it becomes necessary to apply the whole power. The supply in the 
reservoir must be maintained by means of a steam-engine or other suffi- 
cient motor. The presses used for a time in the printing department of 
the United States treasury for printing the notes of the fractional cur- 
rency were operated upon this principle. The same expedient has been 
adopted by Mr. Hesse, of Marseilles, for working hydraulic presses 
employed in the manufacture of oil. The form of stop-cock used by Mr. 
Hesse for communicating with the reservoir, and relieving the press, is 
noticeable for its originality and simplicity. It consists of a small hol- 
low cylinder having three perforations which establish communication 
between the press and the reservoir, or permit the escape of the water 
from the press according as it is drawn out, more or less. The perfora- 
tions are of so small dimensions as to prevent the pressure or the relief 
from taking place too suddenly. 

CHOLLET-CHAMPION'S HYDRAULIC PRESS. 

A very ingenious hydraulic press, designed to be used in the manu- 
facture of wine, was exhibited by Mr. Chollet-Champion, of Blere. France. 
In this machine it is the cylinder of the press which is movable, while 
the piston is fixed and forms the support. The piston, or rather the 
stout cylinder which forms the piston rod, stands in the middle of the 
bed of the press, which is constructed of strong cast iron, and rises to a 
sufficient height to allow for the entire movement of pressure as well as 
for the ultimate depth of the charge. The upper table of the press is 
attached to the base of the cylinder, and in order to produce the desired 
pressure the water is introduced below the piston. What constitutes 



HYDRAULIC PRESSES. 



197 



the peculiarity of this press is the fact that the same charge of water 
serves to maiutain it in operation indefinitely. The cylinder is entirely 
filled in the beginning. If the upper table is raised to its highest point, 
the water will be all above the piston. It is now a reservoir of supply 
upon which the force-pump draws when it is operated to make the 
piston descend. Thus, as the movement advances, the supply of water 
is transferred to the lower part of the cylinder ; and as the piston is 
fixed, the cylinder descends. Fi g- 60 - 

The great advantage of this 
arrangement, apart from the 
incidental convenience of be- 
ing independent of any out- 
ward supply of water, is found 
in the fact that the com- 
mencement of the movement, 
when the resistance is slight, 
takes place without any need 
of applying external force. 
A valve in the piston permits 
the water to pass downward 
freely, so long as the weight 
of the cylinder and the table 
which it carries is superior to 
the resistance, but this valve 
is closed by the pressure be- 
neath, when the force-pump is 
operated. 

From the description thus 

given it will be Seen that While Chollet-Champion's Hydraulic Press. 

the. descending cylinder, with the attached upper table of the press, 
applies a pressure proportioned to its weight, which is therefore pur- 
posely made considerable, it requires some means to be provided for rais- 
ing it which shall not be laborious. The expedient by which this is 
accomplished is a second and small hydraulic press on the top of the 
movable cylinder of the larger one, to which it is firmly secured. This 
small press has a plunger which passes through a packing box into 
the large cylinder, and rests on the piston in that cylinder. When the 
press is at its lowest point, it is evident that both the piston of the large- 
cylinder and the plunger of the small one will occupy the most advanced 
positions possible in their respective cylinders. Let now water be driven 
into the small cylinder by the force pump, and it will by degrees expel 
the plunger, which, resting on the large piston as its support, will lift 
the whole connected mass, including both cylinders and the upper table 
of the press. The length of the plunger being equal to that of the 
great piston, the press is thus easily lifted to the highest point. It fol- 
lows, of course, that the little cylinder, having no work to do but to 
raise the press, is of trivial dimensions compared with the other. 




198 PARIS UNIVERSAL EXPOSITION. 

One additional remark is necessary. Inasmuch, as the piston rod occu- 
pies some space in the cylinder below the piston, it does not require so 
much water to fill the cylinder on this — that is the lower — side of the 
piston, as is required above; and moreover, the small cylinder requires a 
supply, which is discharged when the press descends. At the base of 
the large cylinder, and surrounding it therefore, is attached an annular 
basin, which serves to receive the surplus water during the descent of 
the piston, and to supply the deficiency when it rises. While, therefore, 
the main cylinder is chiefly its own reservoir, this small additional pro- 
vision has to be made, but it is too trivial to occasion inconvenience. 

DESGOFFE & OLLIVIER'S STERHYDRAUXIC APPARATUS. 

The most ingenious and most decidedly original forms of hydraulic 
presses and hydraulic pressure apparatus which presented themselves in 
the Exposition, were what were called by their inventors — Messrs. Des- 
goffe and Ollivier — their "Appareils Sterliyrfyauliques." If the etymology 
of this name does not explain the principle of the contrivance, it will be 
seen to be at least in harmony with it when the principle is known. The 
object of the apparatus, in all its several forms, is to produce a powerful 
hydrostatic pressure by introducing into the cylinder of a hydraulic 
press already filled with liquid, not an additional amount of liquid by 
successive impulses, as is the case in the common hydraulic press, but a 
solid substance, by a steady, unintermitted movement. Or, in the words 
of the inventors themselves, the "Appareils SterlujdyauVic[ues v have for 
their object — 

"1. To obtain a gradual pressure, without jars, by means of a liquid 
hermetically enclosed in a recipient which it fills, and to do this by the 
forcible introduction of a solid body into the recipient. 

" 2. To utilize this pressure by means of one or of several pistons." 

The sole difference — but it is a radical difference — between the old and 
the new forms of hydraulic press, consists in the manner of applying 
the power. In the common hydraulic press, the force exerted through 
the piston of a small forcing pump is intermittent, and acts by fits or 
jolts. But in these contrivances the motive power is employed in intro- 
ducing continuously a flexible cylinder or solid cord, by winding it on a 
pulley which is enclosed within the apparatus, while it is operated by a 
crank or a band wheel on the outside. The pressure produced is there- 
fore gradually and uniformly raised; and it acts upon a piston moving 
water-tight in a cylinder as usual. 

The construction of a press of this kind is illustrated in Fig. 5 of Plate 
Y. P is an external pulley on which is rolled the solid cord, which is 
represented as at the same time partially rolled on the internal pulley 
P'. This internal pulley is enclosed in a strong metallic chamber which 
communicates with the cylinder in which moves, horizontally in the 
present instance, the large plunger S. The driving power acts on the 
pulley P', increasing the volume of the mass rolled upon it. and thus, 
through the confined liquid, acting upon S. By applying the power to 



DESGOFFE & OLLIVIER's STERHYDRAULIC APPARATUS. 199 

the pulley P, and reversing the motion, the cord may be unwound and 
withdrawn ; thus relieving the hydraulic pressure and causing the piston 
S to re-enter under the ordinary pressure of the atmosphere. Although 
the pressure is thus applied gently and gradually, it may nevertheless 
be much more rapidly raised than it is usually convenient to raise it in 
the ordinary form of the pump. For by deriving the force applied from 
the motor of a manufacturing establishment, the pulley may be driven 
with a velocity which would probably soon derange a forcing pump of 
corresponding capacity. The packing of the piston, and of the axis of 
the puliey P', is made of raised or upset leather, as is usual in air pumps. 
That of the cord is simply combed hemp. The liquid in the interior of 
the chamber is oil, and the material of the cord is catgut. This material 
is easily fashioned to a uniform diameter ; it takes a high polish ; it is 
nearly incompressible and inextensible ; it is unalterable in oil; and 
finally, its flexibility adapts it admirably to the purpose to which it is 
here applied. A diameter is generally given to this cord of m .01, or 
four-tenths of an inch. As to the security of the joint formed between 
the cord and its hempen packing, though some appreheDsions were at 
first entertained, they have been entirely removed by experieuce. The 
hemp itself becomes after a time so compacted as to form something 
like a tube of horn, exactly fitting the cord. For five months a press of 
this description in daily use has lost nothing by leakage, nor has it been 
found necessary to tighten the joint. 

In the construction of this press, as the chamber for the liquid is formed 
of a single casting, the pulley P 7 has to be introduced through the open- 
ing left for the piston. Its size being too great to allow this to be done 
in a single piece, it is originally formed of two equal parts, which are 
united on the axis. 

The figure to which reference has been made represents a pump which 
was constructed for Mr. Tresca, of the Conservatoire des Arts et Metiers, 
to be used by him in the course of his investigations on the resistance of 
materials of construction, and the flow of solid bodies. It received, for 
the convenience of these experiments, the horizontal position, and was 
designed to exert a force of 50,000 kilograms. In these investiga- 
tions, the hydraulic press presented the only available means of apply - 
ing the immense pressures necessary; but the intermittent and jerking 
action of the press, as operated by a forcing pump, had the effect of 
determining fracture of the masses compressed before the limit of their 
resisting power to dead pressure had been reached. The perfectly steady 
action of the sterhydraulic press completely remedied this imperfection, 
and eliminated the irregularities which had disturbed the exactness of 
the determinations. 

The ordinary form of the press with vertical movement is shown in 
Fig. 6, annexed. 

In this figure, a manometer appears attached to the press, to serve as 
an indicator of the degree of compression. This is important in experi- 
ments on the resistance of materials to crushing weights. 



200 



PARIS UNIVERSAL EXPOSITION. 



There is one consideration which requires attention in presses con- 
structed on this principle, when it is necessary that the piston shall have 
a large movement. As the quantity of cord accumulated on the pulley 
increases, the resistance to the driving force increases in virtue of the 



Fiff. 61. 




Desgoffe & Ollivier's Sterhydraulic Apparatus. 

enlargement of the radius by which it acts. And this unfavorable effect 
occurs at that part of the course where the pressure on the piston is 
greatest ; and where, accordingly, the mechanical advantage of the motive 
power ought rather to be increased than diminished. To provide for 
such cases, the inventors have devised the form of construction shown 
in Fig. 6 of Plate Y, above referred to, where the pulley is smaller but 
the chamber is elongated, and a second pulley is introduced at the oppo- 
site extremity 5 the cord being in this case rolled about both the pulleys, 
while much the larger part of its mass occupies the interval between 
them. 

A case may however occur, in which a very large piston may have to 
make so long a course, as to render it inconveuient or practically impos- 
sible to meet the exigency by the expedients thus far described: inas- 
much as the quantity of cord required for the purpose might be a trouble- 
some encumbrance. Should therefore this difficulty present itself, the 
sterhydraulic apparatus is constructed in the form of a continuously act- 
ing pump, and is employed to introduce liquid into the cylinder of the 
press, as is done in the ordinary hydraulic press ; only that the entrance 



DESGOFFE & OLLIVIER's STERHYDRAULIC APPARATUS. 201 

of the liquid takes place still in a steady and uniform flow ; and not by the 
spasmodic action which it is so desirable to avoid. The sterhydraulic 
pump is shown in Figs. 7 and 8, PL Y, the first being a side elevation and 
partial section, and the second a profile and section through A B. There 
are now two closed chambers filled with liquid, each having a pulley within 
it, and the cord is transferred alternately from one to the other. The 
withdrawal of the cord produces an aspiration in consequence of which 
the valve at i, at the bottom of the left-hand chamber, Fig. 7, is raised, 
and oil enters through the tube e from an external reservoir, not shown. 
After all the cord has thus been withdrawn from this pulley, and there- 
fore the largest quantity possible of liquid introduced into the chamber, 
the motion is reversed, the cord is coiled again upon the pulley, and the 
consequent pressure, closing the valve i, opens the other valve, also 
marked i, in the valve box between the cylinders. As this valve rises, 
it will be seen that the liquid may escape through the tube g, which 
communicates with the chamber of the hydraulic press, not represented. 
In order that as large a portion of the capacity of each cylinder as pos- 
sible may be utilized, the pulley has arms attached to it at both ends, 
designed to guard the cord from slipping off, or from wedging between it 
and the wall of the chamber ; while the diameter of the coil is increased 
until it occupies nearly the entire body of the pump. 

It will of course be understood that the two cylinders represented are 
entirely alike in construction and in action. While one is drawing liquid 
from the reservoir by its tube e, the other is forcing an equal quantity into 
the chamber of the press by the tube g. At g' is represented a second 
discharge pipe, through which connection may be made with a second 
press, to be operated during the intervals of inaction of the first. 

As it is one of the advantages claimed for this apparatus that it gets 
rid of valves, exception might be taken to the form of it here described, 
on the ground that it reintroduces those objectionable appendages. But 
it will be noticed that these valves open and close only once for each 
reversal of the movement, while during the interval a quantity of liquid 
passes through them nearly equal to the entire capacity of the pump 
cylinders. If we suppose the cord fifty metres long, say one hundred 
and sixty -four feet, it would force, during each alternation, five litres, or 
one and a third gallons, of liquid into the press. A force pump of equal 
diameter and of m .l stroke (four inches) would have to make five hundred 
strokes to accomplish as much $ and thus its valves would have to open 
and close five hundred times as often. And not only would the much 
greater use tend to injure in correspondingly greater proportion, but 
the greater abruptness with which the alternate movements would have 
to be made would have an influence additionally and more than equally 
injurious. 

The constant movement of the valves in the ordinary hydraulic presses 
in which oil is used has the further effect, moreover, to inspissate the 
oil in the valve passages, and on the valve-seats 5 so as both to obstruct 



202 



PARIS UNIVERSAL EXPOSITION. 



their freedom of action, and to prevent them from accurately closing. 
Such consequences do not follow in the sterhydraulic pump. The infre- 
quent opening of the valves produces little if any effect on the oil or the 
metal, and the long continued intermediate flow of the liquid through the 
openings, washes away with it any incipient resinous formation, if such 
occurs. 

The power of the sterhydraulic press may be expressed by a simple 
formula, of which the correctness is obvious. If this power be denoted 
by W, as significant of the weight it would sustain; and if P represent 
the power applied externally to the lever of the driving crank, or to the 
radius of the driving pulley ; and if E is the length of this radius or 
crank lever, and r that of the radius of the receiving pulley within, meas- 
ured to the centre of the cord; while D and d denote the diameters of 
the press piston and of the cord respectively, then we have — 

PED 2 



AT=: 



r d 



If we put P=10 kilograins=22 pounds. 
E=0.25 inetre=10 inches. 
D=0.5 metre=20 inches. 
r=0.1 metre=l inches. 
d=0.01 inetre=0.1 inch, 
the formula above will give 

10 x 0.25 x 0.23 



W= 



=125,000 kilograms, 



Fisr. 62. 



0.1 x 0.0001 

or, say, one hundred and twenty-five tons. As the dimensions here 
assumed are moderate, the immense force which these presses are capa- 
ble of exerting is very apparent. 

Messrs. Desgoffe and 
Ollivier have construct- 
ed a variety of forms 
of apparatus embodying 
the principle above ex- 
plained. In the smaller 
forms of press, a solid 
rod is used instead of a 
cord, for the displace- 
ment of the liquid. Fig. 
9. PI. V. represents what 
is styled by them a labo- 
ratory press, designed to 
separate solids from li- 
quids. The substance 
to be compressed is in- 
troduced into the cylin- 
drical vessel I. which is 
Desgoffe & Ollivier's Seal Press. perforated throughout 




DESGOFFE & OLLIVIER S STERHYDRAULIC APPARATUS. 



203 



its lower portion, and surrounded by a jacket K. The object of 
jacket is to arrest the jets of liquid expelled from the perforations, 



the 
and 



direct them to an annular channel at the 
base, where they flow off through a lip at 
one side. The large motion in this press 
is given, as in a common screw-press, by 
running down the screw F turned by the 
wheel G. D is a horizontal screw enter- 
ing in to the chamber beneath the large 
piston B, which sustains the lower table 
of the press. While the screw F is being 
operated, the screw D is withdrawn to 
its furthest limit; but when the time ar- 
rives to apply the final pressure, D is 
operated by the double crank E, the body 
of the screw entering the cavity and for- 
cing the piston B to rise. 

Another form, somewhat similar, is 
shown in the wood-cut on page 202, Fig. 62. 
This is called a seal press, though it is em- 
ployed for the purpose of forming boxes, 
knife-handles, and the like, out of plastic 
material, by compression in moulds. In 
this case the final pressure is greater, 
and the space through which it is to be 
exerted more limited. The large screw, 
marked U, has therefore a deeper thread, 
which is formed of several spirals. The 
action of this press does not differ mate- 
rially from that of the last, the fin il pres- 
sure being given by the screw v ; but it 
is much more massive in proportion to 
the extent of movement which it admits, 
and the force which it is capable of ex- 
erting is correspondingly greater. 

But the purposes to which the "appar- . 
eils sterhydrauliqiies" are applied are more 
various than would be anticipated in re- 
garding them as simply presses. One of 
these is for testing the tenacity of wire 
under a force of longitudinal tension. In 
experiments of this description, it is im- 
portant that the force should rise stead- 
ily, and not by intermittent jerks; both 
because the effect of a sudden twitch is 
to break the wire prematurely, and be- 
cause a strain rising by steps does not 



Fig. 63. 




Apparatus for testing the tensile 
strength of wire. 



204 PARIS UNIVERSAL EXPOSITION. 

furnish an exact measure of a resistance which may fall between its 
successive values. The steimydraulic' gauge is not liable to either of 
these objections. Its construction will be made intelligible by an exam- 
ination of Fig. 63, annexed. In this, S represents a solid and rigid 
base to which the whole apparatus is secured. G G 7 are cylindrical 
rods or columns serving to guide the slides M-j and M 2 , which carry the 
jaws designed to hold the wire. The construction is such as to make 
these jaws act automatically, closing them more firmly in proportion as 
the force of tension is greater. E is a bevel gear wheel acted on by 
another similar wheel on the axis of the double crank m. By turning 
this crank the screw V is advanced or withdrawn, so as to admit the 
introduction and the subsequent stretching of the wire F. 

The sterhydraulic part of the apparatus is seen at B, and is repre- 
sented in section in the small figure above. The cylinder B is filled 
with water, e, which is confined by a diaphragm of India-rubber. The 
piston P presses against this diaphragm. By means of the cross-head 
K, and the lateral bars shown in the cut, it is connected with the jaws 
which grasp the wire at M 2 , and thus the entire strain upon the wire is 
brought to bear upon the liquid confined in E. M is a manometer to 
which this pressure is transmitted through the tube which serves as its 
support. The index of the manometer advances as the pressure rises, 
carrying with it a register index, which, on the rupture of the wire, 
marks exactly its final strain. By means of a scale and vernier on one 
of the columns carrying the slider M l7 the amount of stretching of the 
wire under determinate strains may from time to time be measured. 

Another form of the apparatus is designed to test the resistance of 
solids to cross-strains. For resistance to crushing forces, the ordinary 
form of the press suffices. All these contrivances show ingenuity, and 
there can be no doubt that they are destined to render material services 
not only to industry but to mechanical science. 

ASCENSEUR EDOt'X. 

The elevator of Mr. Leon Edoux, designed to lift weights by hydraulic 
pressure from level to level, though in its actual application employed 
only to elevate persons from story to story in public hotels, has naturally 
its place here, since in principle it in no respect diifers from an ordinary 
hydraulic press in which the plunger has a length excessively exaggera- 
ted in comparison with its diameter. Two elevators of this description 
were constantly in operation during the Exposition, in the gallery of 
machines; and the number of visitors who took advantage of them for 
the purpose of ascending to the roof of the palace, and enjoying the ex- 
tensive view which that commanded, amounted probably to some hun- 
dreds of thousands. The essential parts of this apparatus consisted of a 
cylinder twenty metres (sixty-six feet) long, sunken perpendicularly into 
the earth, with a plunger descending into it to the same depth, and packed 
water-tight at the top of the cylinder. Into this, below the packing, water. 



HYDRAULIC ELEVATORS. 205 

from the source from which the Exposition received its supply for gene- 
ral purposes, was admitted, by means of a valve which was under the 
control of the attendant. The piston rose under the pressure to the re- 
quired height, and was maintained there by closing the valve. 

A car or kiosk, for the accommodation of passengers, rested on the 
upper extremity of the pistcfn, and was elevated as it rose. The descent 
was effected by opening another valve which allowed the water to escape 
at the level of the earth's surface ; when, the pressure being relieved, 
the car descended by its own weight. The diameter of the piston plun ger 
was 0.25 metre, (ten inches,) and that of the cylinder only sufficiently 
greater to allow free water-way. The plunger was a hollow casting, 
turned and polished on the exterior, and closed at the bottom. It was 
formed of four lengths carefully united. A strong wire cable extending 
through the interior from end to end firmly bound the parts together, 
and served as a security for holding them in position in case of the oc- 
currence of any accident. 

In its ascent, the car was guided by four cast-iron columns, which 
formed a rectangular framework or tower around it. These columns 
were hollow also, affording space for the ascent and descent of heavy 
weights within them, by which the weight of the empty car was princi- 
pally counterpoised. Chains passing over pulleys at the top connected 
these weights with the car at its four angles. Only sufficient prepond- 
erance was given to the car to allow it to descend without a load. The 
resistance to which the hydraulic pressure was opposed amounted, there- 
fore, to little more than the weight of the varying charge. 

It is to be noticed, however, that as the car ascends, the weight 
opposed to the pressure virtually increases, since the plunger, so long 
as it is immersed, is buoyed by the weight of an equal bulk of water. 
A compensation for this increase of resistance is provided by Mr. iMoux, 
in giving to the chains a weight per running foot equal to the eighth 
part of the thus accruing increase of weight of the piston — that is to say, 
about two kilogrames, or a little more than four pounds. There being 
four chains, and each chain being diminished one foot in length on the 
side of the car, and increased in length on the side of the counterpoise, 
one foot for each foot of elevation, the counterpoise is thus increased at 
the same time fifteen kilogrames, or about thirty-four pounds, which is 
equal to the simultaneous increase in the virtual weight of the piston. 

The charge which an apparatus of this kind will elevate, the cross- 
section of the piston remaining the same, will depend on the height of 
the hydraulic head. If we assume the system of counterpoises to be such 
as to maintain the whole moving apparatus (supposed to be without a load) 
in equilibrio when the pressure of the head is shut off and the escape valve 
is open, or with only a slight predominance of weight in favor of descent, 
and to do this in every part of the course, the elevating force will be 
found by making the proper substitutions in the expression 

F=i * dhvh, 



20fi PAEIS UNIVERSAL EXPOSITION. 

iii which F represents the force, d the diameter of the piston, ic the 
weight of a cubic unit (metre or foot as the case may be) of water, and h 
the height of the head. It was stated that the reservoir from which the 
supply of water was received was situated at an elevation of thirty metres 
above the point of application. Putting, therefore, h=30, tf=0.25, and 
2C=1 ? 000 kilogranies, we shall obtain the result 

F=3.14159x 0.0625 x 30 xl,000-^4==l,473 kilograms nearly. 

Putting the average weight of an adult at sixty kilograms, say one 
hundred and thirty pounds, the ascenseur was capable of carrying up 
twenty-tour or twenty-five persons at a time, and it usually went up 
full. There were in fact two ascenseurs working side by side; and they 
were constantly in motion from eight o'clock in the morning till six 
o'clock in the evening ; making an ascent and descent at least as often 
as every ten minutes, or even usually in less than half that time. 3Iore 
than three thousand persons ascended each day, sometimes more than 
live thousand. 

It will be seen that the ingenious system of counterpoises introduced 
by 3Ir. Edoux makes the height to which the charge is elevated quite 
independent of the height of the hydraulic head. Other considerations, 
however, practically limit the extent to which the system can be applied. 
In proportion as the length of the piston is increased it becomes neces- 
sary to increase its diameter and the thickness of its walls, in order that 
it may preserve a sufficient rigidity under the increasing strain and 
pressure to which it will be liable. Its weight will be correspondingly 
increased, entailing the necessity of equally increasing the weight of the 
chains and counterpoises. Thus the apparatus will become too ponder- 
ous to be advantageously employed. The weight of the pistons of the 
ascenseurs in the Exposition was two thousand one hundred kilograms, 
or more than two tons each. This weight exceeded, therefore, alone, 
not considering the cars, the whole force of elevation, by more than 
six hundred kilogranies; so that without the system of counterpoises 
the apparatus would not have worked at all. 

On the other hand, for the ordinary purposes of a hotel elevator, it is 
not necessary to have a source of water by any means so high above the 
point of application as that which operated the ascenseurs of the Exposi- 
tion. It is sufficient, we will suppose, that such an elevator may be 
capable of carrying up eight persons at a time, having a total weight of 
ten to eleven hundred pounds. Assuming an outside weight of twelve 
hundred, and, transforming the expression above for the value of h. we 
have — 

x £F _ 4800 x 111 _ 

-cT-ic 3.11159 x 100 x 6±o ~ 3 ° feet nearly, 
putting the diameter of the piston at ten inches, and taking 62.5 pounds 
as the weight of a cubic foot of water. 

If the diameter of the piston be enlarged to twelve inches, the hydraulic 
head required will be but twenty-four feet. Such an elevator can there- 



HYDRAULIC ELEVATORS. 207 

fore be introduced into any house in which the water rises to a height of 
thirty-five feet, or even twenty-four feet, above the lowest point at 
which it can be conducted off after being discharged. It is desirable, 
of course, to have a superfluity of force, but that can abundantly be 
obtained in any house in which water from the public works is delivered 
in the third story, and communication with the public drains can be 
established from the basement. 

Hydraulic elevators in dwellings have the advantage over mechanical 
contrivances for the same purpose worked by steam-engines, turbines, 
or other motors, because of their simplicity of construction, their extreme 
facility of management, their perfectly smooth and silent motion, and, 
in general, their large superiority in point of economy in operation. The 
economy, however, may not be realized in large cities, where water 
rates are high ; but the advantages are in other respects so much in 
favor of these elevators, especially when the security attending their 
use is also taken into consideration, as to justify their introduction even 
in cases where it might be necessary to create the hydraulic head by 
means of steam-pumps. If steam power has to be used at all it may as 
well be employed in elevating water as in directly operating an elevator. 
And if this plan is once adopted the establishment becomes independent 
of public water-works, and even of natural sources altogether, after 
having provided a moderate original supply, since the same water may 
be constantly used over and over again. It will be necessary for this 
purpose to have a tank at the lowest level and another at the highest. 
And if we assume (as has been shown above to be just) a height of thirty- 
five feet to be sufficient in ordinary cases, it is not difficult to compute 
the work which an engine would have to perform in lifting the water 
required for the daily service from the lower tank to the upper. 

Supposing the course of the piston to be sixty feet, and its diameter, as 
above, ten inches, it will require an exj)enditure of about thirty- three 
cubic feet of water for each ascension. Supposing an ascension to take 
X>lace every six minutes, or ten every hour, which is about the fact at 
the Charing Cross Hotel, in London, and that the elevator is in operation 
eighteen hours a day, i. e., from six in the morning until twelve at night, 
the total daily expenditure of water will be five thousand nine hundred 
and forty cubic feet — say six thousand — to raise which thirty-five feet 
gives a total work of 13,125,000 foot-pounds. This work a one-horse 
power engine would do in a little more than six hours and a half. 

It would not be desirable, however, to raise the whole quantity at 
once, nor even desirable to have so large a quantity at a time in the 
tanks, since the weight of six thousand cubic feet of water would be 
somewhere near one hundred and ninety tons. A tank capable of con- 
taining two hundred cubic feet would suffice for six ascents ; and if an 
engine should be employed, constantly in raising the water as it is drawn 
down, one-third of a single horse-power would exceed the demand. Such 
an engine could probably be run at a much less cost than is paid in Lon- 



208 PARIS UNIVERSAL EXPOSITION. 

don for the supply of the elevator of the Charing Cross Hotel, which was 
stated to exceed a pound a day. 

HYDRAULIC COUNTERPOISE SYSTEM! OF MR. EDOUX. 

Although the invention does not fall properly under the head of 
machines operating by hydraulic pressure, yet the plan contrived by the 
originator of the elevator above described, for raising heavy masses, 
especially building materials, by the aid of hydraulic counterpoises, may, 
without impropriety, be introduced here. It is extremely simple, but 
where its introduction is practicable, it would seem likely to be of great 
utility to the builder. Two tall tripod frame- works are constructed near 
each other, within each of which ascends and descends a large tank 
made of rolled iron. Upon the top of this tank is a platform for the pur- 
pose of receiving the materials to be elevated. The tanks, with their 
platforms, are both attached to the same endless chain, which passes 
over pulleys at the tops of their respective frames. They are related to 
each other in the same manner as ascending and descending trains upon 
the inclined planes of some railroads, of which the heavier, in its descent, 
draws up the lighter ; that is to say, their movements are in opposite 
directions, and when one is down the other is up. Supposing, now, the 
platform which is on the ground to be loaded with materials, its tank 
being at the same time empty, it is only necessary to lead the water of 
the city supply to the upper tank by means of a hose ; and so soon as 
the weight of water, thrown in this manner into the upper* tank exceeds 
the weight of the charge on the lower platform, it will descend by its 
superior gravity and the load will be raised. The chain being continu- 
ous, both below and above both the two tanks, its weight will produce 
no effect in disturbing the preponderance, in whichever way it shall have 
been established. A system of clamps, or brakes, provides for the arrest 
of the movement at any desired point. After the removal of the load, 
the empty tank may in its turn be filled, the water having been dis- 
charged from the full one at the bottom by means of a valve ; and thus 
the process can be indefinitely continued. 

In order that this system of elevating heavy masses may be practica- 
ble, it is of course necessary that the water supply of the town in which 
it is proposed to use it should be sufficient to justify such an application ; 
and also that the cost of the water should be less than that of the labor of 
men, or of the operation of machinery, which it replaces. In Paris, both 
these questions seem to be settled favorably to this apparatus. In Xew 
York, probably neither would be. But if it were otherwise, the adoption 
of this very simple contrivance would relieve very much the labor of 
erecting lofty buildings out of ponderous materials, and would probably 
very sensibly accelerate the process of construction. 

GIRARD'S "PALIER GLISSAXT." 

The term " palter gli&scmt" which does not admit of being very hap- 
pily translated into an English term of equal brevity, is the name given 



girard's frictionless support. 209 

by the inventor, Mr. Girard, to a frictionless support, or socket, designed 
to sustain the axes of heavy wheels in machinery. Since it is a contri- 
vance deriving its efficacy from hydraulic pressure, it may, without 
impropriety, be considered here. The friction of axles in their supports 
is the occasion of a considerable loss of power in every machine. The 
loss of power itself, though a real disadvantage, is nevertheless a matter 
of secondary consequence compared with the attendant elevation of tem- 
perature, which, were not means carefully provided for reducing friction 
to the lowest point possible, might soon be so great as to arrest the ope- 
ration of the machine itself. It was stated in a public lecture delivered 
in May, 1867, before the Scientific Association of France, that, in a cer- 
tain instance Avithin the lecturer's knowledge, the screw shaft of a French 
naval propeller became absolutely welded to its support, though sur- 
rounded by the water of the sea, in consequence of the great heat devel- 
oped by its revolution. 

The ordinary means of reducing friction is to apply oil, or some other 
unctuous substance, to the parts which move upon each other. Some 
disadvantages attend this expedient, but till a better is suggested, they 
have to be endured. The cost of the oil expended in maintaining in 
proper condition the axles of the machinery in a foundry, or of the roll- 
ing stock of a railroad, amounts to a large sum annually ; while the want 
of neatness which its use makes, to a certain extent, inevitable, and the 
labor which must be constantly employed to prevent this want of neat- 
ness from becoming much greater than it is, are serious items to be set 
off against its positive usefulness. 

The object of Mr. Girard is to get rid of all these drawbacks by the 
simple expedient of substituting water for oil. It would not avail to 
apply water precisely as oil is applied. Though any one's experience 
may tell him that two smooth pieces of metal will slide more easily on 
each other when they are wet than when they are dry, yet every one 
knows also that oil facilitates the movement much more perceptibly than 
water ; and also, that in the case of oil there is no difficulty in maintain- 
ing the lubricating film, whereas water easily evaporates, and in case of 
the accident of even a moderate elevation of temperature, it would be 
expelled from the joint entirely. Mr. Girard proposes, therefore, to 
employ the water to act, first, by its pressure, to lift the journal to be 
lubricated $ and secondly, by its fluidity, to form a liquid bed or cushion 
between the journal and its box, on which the journal may rest in its 
revolution, without touching the metal of the box at all. 

The construction will be understood by referring to the figure. One 
of the journals is represented as removed, and in the cylindrical surface 
of the socket are seen grooves occupying a considerable part of the area 
exposed. These grooves communicate, by an aperture in the middle, 
with a tube which is represented externally, and w r hich sends a branch 
to the other journal, through which water under a heavy pressure is 
introduced into the box beneath the journal. The effect of the hydraulic 
14 I A 



210 



PARIS UNIVERSAL EXPOSITION. 



pressure is to lift the axle, opening a passage for tlie escape of the com- 
pressed water, which at the same time, because of its release from com- 
pression, loses the power to sustain the weight. If, therefore, by the first 



Fig-. 64. 




impulse, the axle 
is thrown upward 
to any sensible dis- 
tance, it will imme- 
diately fall back 
again, once more 
confining more or 
less completely the 
water. After one 
or two oscillations, 
therefore, the axle 
will settle itself at 
length in a position 
in which, while the 
water will escape, 
it will escape but 
as a film of inap- 
preciable thickness. 
In this condition 
Girard's Palier Glissant. the journal turns 

upon a liquid bed, and the resistance to its revolution is so excessively 
small that a slow rotation given by hand to a wheel sustained by it 
will be maintained for many minutes without perceptible retardation. 
In fact, the most striking illustration which can be given of the immense 
superiority of the palier glissant over a support lubricated in any 
other way, is furnished by placing two precisely similar wheels or 
disks side by side, weighing five or six pounds each, with a diameter 
of seven or eight inches, and journals of half an inch in diameter ; 
one of them furnished with palier s glissants, and the other with boxes 
lubricated with fine oil. Give each of them a velocity of rotation of 
about one revolution in a second ; the one lubricated with oil will come 
to rest before the other begins to give evidence of any sensible retarda- 
tion 5 but if at any moment the stop-cock which supplies the water to 
the second be turned, this one will also stop, and its stopping will be 
instantaneous. 

It might be supposed that a journal supported in the manner above 
described would be unsteady and liable to injurious vibrations. This 
is not the case, and it is easy to see why not. When the journal is truly 
in the middle of the socket, that is to sayAvhen there is an equal distance 
between it and the wall of the socket on either side, it will be equally 
pressed from both sides. But if it is in the least displaced laterally, the 
pressure on the side toward which it moves will instantly increase, while 
that on the other side will correspondingly diminish : both causes con- 



girard's frictionless support. 211 

spiring to resist the displacement, and to maintain the journal in the 
position of true equilibrium. Suppose, for instance, that a weight of 
one ton is supported by a journal four inches in diameter, which has a 
bearing of ten inches in length. The horizontal section through this 
journal would have an area of forty inches. Of the total water pressure 
beneath the journal the total upward component must be equivalent to 
fifty pounds per square inch ; but considering that this is the upward 
component of a uniform pressure directed perpendicularly upon a semi- 
cylindrical surface, the total absolute pressure must be greater in the 
same proportion as half the square of the diameter is greater than half 
the area of the circular section of the axis. That is, if P be the abso- 
lute pressure per square inch, p the mean upward pressure per square 
inch of horizontal section, and r the radius of the axis, then 

P : p : : 2r 2 : — : : 4 : - : : 14 : 11 nearly. 

Whence the absolute pressure must be sixty-four pounds per square 
inch. If we consider however that it is not the whole surface of the 
journals which is pressed upon when the water is first admitted, but 
only the portion opposite the grooves, which we may assume to be half 
the total surface, it follows that the pressure in the reservoir must be 
double this, or one hundred and twenty-eight pounds to the square 
inch, which is a little over eight atmospheres. If, now, while the axis 
is in the central position of equilibrium and resting on its watery cush- 
ion, a force be applied to urge it laterally, this force will be resisted by a 
contrary lateral pressure equal to half the weight sustained — that is to 
say equal to half a ton, while the counter-pressure on the opposite side 
will fall oif on the slightest movement ; so that it is apparent that the 
lateral stability is no less than the vertical. 

The water pressure by which these "slippery supports" are supplied 
must be created by a force pump worked by the machine itself. The 
reservoir need not be large, as the expenditure of water is very minute 
in volume. To the objection which may naturally be made, that the 
working of the pump must be a tax on the motive power without return, 
a reply at once simple and satisfactory is found in the experience of Mr. 
Girard, that the working of the pump does not consume so much as 
half, and sometimes not more than one quarter, of the power which is 
lost in friction when the ordinary modes of lubrication are employed ; so 
that by the adoption of this expedient the available power of the 
machine is very sensibly increased after deducting all that is expended 
in the performance of this additional work. 

The palier glissant is an invention analogous to, or rather identical 
with, another by the same ingenious engineer, which has been already 
mentioned in speaking of turbine wheels, the hydraulic pivot. In that 
case the whole weight of the turbine and its shaft is sustained upon a 
cushion of water, precisely as here a similar cushion sustains the hori- 
zontal axis of a machine. 



212 PARIS UNIVERSAL EXPOSITION. 



MISCELLANEOUS APPLICATIONS OF HYDRAULIC PRESSURE. 

The applications of hydraulic pressure iu the useful arts are becoming 
continually more extensive and varied. One of the most interesting of 
these has been made by Mr. Whit worth, who has patented an apparatus 
for subjecting steel to an intense pressure during the process of casting, 
and while it is becoming solidified in the moulds. The object which the 
inveutor has in view is to secure sounder castings, and to render it 
unnecessary to use great heads of metal. The results are said to have 
been extremely satisfactory. 

Another application of the same power in metallurgy is illustrated in 
the punching machines, exhibited in Class 54 of the Exposition, by 
Messrs. Tangye Brothers, of Birmingham, designed to punch the holes 
through the webs of steel rails, near their extremities, which are required 
in "fishing 77 joints. In this machine a very small movement suffices to 
effect the object; but very great power is necessary. Two holes are 
simultaneously punched, each being one inch by one and a quarter in 
dimensions. The pressure is applied by means of a hydraulic cylinder 
of fourteen inches diameter; and the water is supplied from an accumu- 
lator having a compressed air chamber, in which the pressure is raised 
to three hundred atmospheres. The total pressure which the press is 
capable of exerting amounts therefore to nearly four hundred tons. The 
upward stroke is effected by means of a smaller cylinder, and this 
smaller cylinder is always in communication with the accumulator, so 
that the small piston always tends to lift the ram and punches. When a 
down stroke is to be made, the water is admitted to the main cylin- 
der by opening a stop-valve, this valve being combined with a discharge- 
valve, which is opened on the completion of the down stroke, the ram 
being then raised by the action of the small piston, and the water in the 
main cylinder flowing off through the waste-pipe. The punch holders 
at the bottom of the ram are so fixed to the latter that they can be 
readily adjusted to suit different pitches of holes. 

IY.—MECHAXICAL PBESSES. 

For applications of pressure which require but a short range of move- 
ment combined with energetic action, the principle of the hydraulic 
press is, in general, most advantageous; although in some cases, as in 
coining, in which rapidity of action is important, this is not well adapted 
to the purpose, and the effect desired is produced by eccentrics, knee- 
joints, &c, with the aid of heavy riy-wheels. But there are many ope- 
rations of industry in which large movement is necessary, accompanied 
by a pressure gradually increasing and becoming in the end very intense. 
Such, for instance, are the expression of the juice of grapes or apples, or 
the reduction of the volume of substances like cotton and hay into the 
form of portable bales. Eor cotton pressing, the direct action of steam 
is advantageously employed in our southern seaports : but steam presses 



MECHANICAL PRESSES. 213 

are not economically available for rural industries, and it is a problem on 
which much ingenuity has been expended, to construct a compressor 
which shall combine the advantages of original cheapness, large range 
of movement, simplicity of construction, and great ultimate power, 
without requiring any other force to operate it than is furnished by 
human strength. In countries in which the culture of the vine furnishes 
employment to a large proportion of the population, it is natural to look 
for numerous mechanical contrivances designed to fulfil these condi- 
tions. Many varieties of mechanical presses intended especially for the 
use of wine growers, but applicable with advantage to other analogous 
industries, were present in the Exposition, chiefly in the French depart- 
ment. In these the aim of the inventors, in nearly every instance, had 
been to produce mechanical combinations capable of being adapted, 
with facility and expedition, by variations in the adjustment of the 
mechanism, to the varying resistance required to be overcome in different 
parts of the course. In the ordinary simple screw-press a given velocity 
of the moving force produces an equally unvarying velocity of the compres- 
sion platen. If the press is designed greatly to multiply the force, this 
velocity must be small ; and in that case a press of long range will be 
very slow in action. When a very yielding substance is under compres- 
sion, it is possible, by proper mechanical contrivances, without accelerat- 
ing the movement of the power or imposing upon it a work which it can- 
not perform, very greatly to increase the velocity of the platen with a 
corresponding economy in regard to the time of the operation. In 
nearly all the presses exhibited, this effect is produced by systems of 
gearing which admit of being differently connected in the different stages 
of the compression, so as to vary correspondingly the velocity of the 
platen. In one of them, however, the knee-joint principle is employed, 
in which the effect of straightening the branches is necessarily to diminish 
the velocity of movement while increasing the intensity of the pressure. 
A very common mode of constructing these presses is to make the screw 
itself a fixed part of the construction, rising from the lower table or bed 
of the press, as in the hydraulic press of Mr. Chollet-Chainpion, above 
described, through the mass of the substance to be compressed. This 
construction necessarily assumes that it is not the substance which 
remains under the press after the operation is over which is to be pre- 
served, but that which is expelled from it. Such presses are adapted to 
the manufacture of wine or cider, or to the expression of oil from olives, 
but not to cotton pressing or the reduction of merchandise of any kind 
into smaller compass for the sake of portability. In all the presses of 
this description, therefore, the force is applied to the nut, which descends 
along the fixed screw and drives the platen before it. In general this 
nut is constructed in circular form and of large diameter, and is geared 
on its circumference, sometimes with spur gearing, sometimes with 
bevel gearing, and sometimes with an internal gearing; the nut in 
this case being constructed with the form of a lid of a box in order to 
receive it. 



214 PARIS UNIVERSAL EXPOSITION. 

LOTTE ? S PORTABLE WIKE PRESS. 

A very neat press of this kind, mounted on wheels, was exhibited at 
the island of Billancourt by Mr. Lotte. In this press the nut is a spur- 
wheel of five feet in diameter, driven by a vertical pinion three feet in 
length, and in diameter only four inches. This pinion is then driven by 
another pair of gear wheels which multiply the force nine times, and 
finally the power is applied by means of a fly-wheel of about two feet in 
diameter provided with handles. The long pinion is easily thrown out 
of gear, whereupon the power is directly applied to the nut by means of 
handles at right angles to its upper horizontal surface, aud the press is 
rapidly run down. This press, operated by a single man, gives a pres- 
sure of forty-eight tons upon a surface of about fourteen square feet, or 
nearly three and a half tons per square foot. 

LEMOXNIER AND XOUVIO^'S PORTABLE PRESS. 

Another press, also on wheels, exposed by Messrs. Lemonnier and 
^ouvion at Billancourt, is very similar to that of Mr. Lotte, inverted : 
that is to say, the screw is attached to the platen, and passes downward 
through the bed of the press, the nut being applied beneath the bed. 
Here, moreover, instead of the long, vertical pinion, which would not 
be so convenient, a bevel-geared short pinion acts on the nut, which is 
fixed in position, and, in turning, draws the screw, and with it the platen, 
downward. A second gearing drives the piuion ; and finally, as before, 
the power is applied to a fly-wheel. The movement may be accelerated 
by changing the system of gearing actually engaged, there being pinions 
of different sizes capable of being brought into action interchangeably. 

CHOLLET-CHAMPIOX'S MECHANICAL PRESS. 

A number of presses were exhibited having two parallel screws, both 
operated at once by one driving power through corresponding systems 
of gearing. But the best of all the mechanical presses operated on this 
principle exhibited, was one by Mr. Ohollet-Chainpion, whose hydrau- 
lic press has been already described. This press is represented in 
the accompanying Fig. 65, and the system of gearing will be made 
more intelligible by reference to the enlarged representation in Fig. 
66. There are three arbors to which the crank can be applied, each pro- 
ducing a different velocity of movement in the platen. The enlarged 
lateral view will show that the upper two of these are the axles of pin- 
ions which can be thrown into gear with a larger wheel below them : 
and that the third is the axle of this larger and lower wheel itself. 
Upon the same arbor with this wheel is a bevel pinion which engages a 
large horizontal wheel correspondingly geared. The vertical arbor of 
this horizontal wheel carries a pinion which acts on an internal gearing 
in the last wheel of the series, which is the nut applying the power 
to the platen. The base of the construction carrying this system of 



chollet-champion's mechanical press. 



215 



gearing is firmly secured to the platen, and the whole apparatus rises 
and falls with the movements of the press. 
The smallest of the pinions to which the crank can be directly applied 



has nine teeth, and the larger 
one fifteen. The wheel into 
which these pinions gear has 
forty-five teeth. The bevel 
pinion has ten teeth, and the 
bevel wheel which it actuates 
forty-two teeth. The pinion on 
the vertical axis of this wheel 
has again ten teeth, and the 
internal gearing sixty-five 
teeth . The 1 en gth of th e crank 
is one-third of a metre, the di- 
ameter of the screw one deci- 
metre, (four inches,) and 
the distance between the 
threads twenty-seven millime- 
tres, (about an inch.) 

The force is applied succes- 
sively, as follows : First, di- 
rectly to the large upper wheel 
or screw-nut, marked D ; then, 
by placing 



Fig. 65. 




Chollet-Champion's Mechanical Press. 

the crank on the axis of the vertical wheel E, which, by the 

Fig. 66. 




Chollet-Champion's Mechanical Press — enlarged view of upper portion. 

conical gearing and the gearing of the internal pinion and the wheel D, 
gives one turn of the nut of the press for twenty-seven turns of the 



216 



PARIS UNIVERSAL EXPOSITION. 



crank. When the resistance becomes too great to continue with this. 
the fifteen-toothed pinion is brought into gear with the wheel E, and 
the crank transferred to its axis. This combination gives one turn of 
the nut to eighty-one turns of the crank. Afterwards the fifteen T toothed 
pinion is thrown out of gear and the nine-toothed pinion thrown in. 
This gives a turn of the nut to one hundred and thirty-six and a half 
of the crank, and is the largest multiplication of force of which the 
machine admits. With this combination a man, by applying to the 
crank a force of fifteen kilograms, or about thirty-two pounds, can exert 
a pressure of nearly fifty tons on the entire surface of the body com- 
pressed. This press, for its neatness, compactness, and strength, is 
worthy of high commendation. 

samain's knee-joint press. 



One other only of these mechanical presses will be noticed, and tbat 
for its peculiarity of employing the principle of the knee-joint for high 
compression combined with pretty large movement. The knee-joint 



Fisr. 67. 




Samain's Knee-joint Press. 

press is recommended by several advantages. It acts spontaneously to 
increase the intensity of the pressure, when by the reduction of vol 



217 

nine of the mass compressed the resistance becomes greater 5 and as the 
limit of the movement is approached, the ratio of the power to the resist- 
ance becomes mathematically unlimited. The construction is simple, 
and the loss of useful effect by friction is less than in the presses which 
act through gear-wheels. On the other hand, in a press of this descrip- 
tion a large range of movement cannot be obtained without giving to 
the machine much greater dimensions than are necessary in ordinary 
presses of equal power. The press represented in the annexed figure 
was exhibited by Mr. P. Samain, of Blois, France. It is constructed of 
several sizes, furnishing an actual pressure of from twenty to one hun- 
dred tons. The smallest is about seven feet, and the largest about 
twelve feet, in height. 

As the 'figure shows, the power is applied by means of a double knee- 
joint articulated at the top to the upright framework, and at the bot- 
tom to a cross-head, from which proceeds the shaft which applies the 
force, and which works through a guide. At the junction of the 
branches the articulations are made with masses of metal forming 
screw-nuts, through which passes a horizontal screw, right-handed for 
one-half its length, and left-handed for the other half. This screw is 
operated at first by means of a set of crank-handles at one end of it ; and 
when the resistance becomes very great, by means of a counterpoised 
ratchet lever, which is shown in the middle of the frame. The force 
applied in this way is very great, since the operator can act on the lever 
with his whole weight. 

The frame of this press has been constructed by the inventor so as to 
serve as a dynamometer, showing the amount of pressure at any time 
exerted. The head-piece into which the arms articulate is connected 
with the body A by means of iron or steel bars, having a certain curva- 
ture which the pressure tends more or less to straighten, according to 
its intensity. An upright needle, which is seen in place at the left-hand 
extremity of the cross-head, is moved, as the straightening goes on, pro- 
gressively toward the right, and its upper extremity indicates the degree 
of pressure upon a fixed scale attached to the frame. This needle has 
likewise another function to perform. As, theoretically, when the 
branches of the knee-joint are nearly in a straight line, the force 
approaches infinity, there is a possibility that, in certain circumstances, 
the parts under strain may be fractured. In order to prevent the occur- 
rence of an accident of this kind, an arm attached to the frame at d is 
moved by the needle toward the lever ; and when the limit of safety is 
reached this arm interposes an obstacle to the movement, and makes it 
impossible for the operator to carry the pressure further. 

The knee-joint press, though rarely seen in use, is not a novelty ; but 
the model presented by Mr. Samain is conveniently arranged, and the 
dynamometrical feature, which is original, is a very useful addition. A 
press on this principle has been in use in Mobile, and perhaps in other 
southern seaports, for pressing cotton. In order to adapt it to a pur- 



218 PARIS UNIVERSAL EXPOSITION. 

pose requiring so large a range of movement, it is necessary to construct 
it upon a pretty large scale. The knee-joint cotton presses of Mobile, 
which are worked by steam, are in height not less than twenty-five or 
thirty feet. 



CHAPTER VII. 

METERS FOR LIQUIDS AND FOR GAS -BOILER 

FEEDERS. 

Spirit meter of Siemens and Halske— Volumeter and alcohometer— Duboys's 
water meter — clement's water meter— payton's — cochrane's meter for 
liquids flowing under pressure— gas meters— suggs's photometric gas- 
MEASURING apparatus — Constant level meter — Boiler feeders — Riedel's — 

HOUGET & TESTON'S. 

L—METEBS FOE LIQUIDS. 

Instruments designed to measure and record the quantity of a liquid 
or of a gas passing through them were present in the Exposition of 1867, 
as in former Expositions, in numbers. The most elaborate and certainly 
the most ingenious of these was one which was exhibited by Messrs. 
Siemens and Halske, of London, and which was designed by them as a 
meter for alcohol. In addition to the measurement of the volume, a 
function to which in general contrivances of this class are confined, it 
is the purpose of this apparatus to register the quality of the liquid ; 
that is to say, the amount of absolute alcohol contained in the measured 
volume passing through it. Two sets of register dials therefore appear 
on its face; upon one of which may be read the total volume of the 
liquid which has passed, while the other shows the total amount of 
absolute alcohol which the whole contains. 

SPIRIT METER OF SIEMENS AND HALSKE. 

This instrument embraces, therefore, two distinct pieces ot apparatus 
which may be separately described. The volumeter consists essentially 
of a hollow drum divided by a concentric cylindrical partition. In the 
annular cavity between the two cylindrical surfaces there are constructed 
three separate chambers, each capable of containing five litres. The 
liquid is received into the small central cylindrical space through the 
axis of rotation. Three slits in the cylindrical partition permit the 
liquid to flow successively into the chambers according as each in 
turn occupies the lowest position. The openings are so arranged that, 
while the lower chamber is filling, the level in the receiving cavity is 
too low to permit an escape into either of the others ; and it remains 
stationary until the lower chamber is quite full. It then rises and the 
liquid begins to overflow into the chamber next following in the order 
of rotation, increasing the weight on that side and causing that chamber 
to descend. The discharge of the full chamber then commences, while 
the aperture through which it received its supply is carried by the rota- 



220 PARIS UNIVERSAL EXPOSITION. 

tion above tlie level of the liquid in the central cavity. In order that 
no outflow may take place until this change of position has occurred, 
the channels of discharge are carried spirally from each chamber round 
the exterior of the one next following, in form something like the curved 
floats of a turbine wheel. A rotation of about 60° from the stationary 
position is necessary before the discharge can begin. The liquid then 
flows into a tank which surrounds the lower portion of the drum, and is 
conducted off by suitable arrangements. By the rotation of the drum 
the registering dials are actuated in the usual manner. 

The portion of the apparatus by means of which the amount of pure 
spirit is determined and recorded consists, in its principal feature, of a 
hydrometer on a large scale, floating in a vessel through which the 
liquid passes on its way to the volumeter. This float is constructed of 
thin sheet brass, and is filled entirely full with strong spirit. The air 
having been expelled by boiling, it is then hermetically sealed. This 
expedient makes the hydrometer practically independent of the fluctuat- 
ing temperature of the liquid measured, inasmuch as the changes of 
density of the float Avill be sensibly the same as those of the liquid itself. 
The stem of the float is connected with the short arm of a lever which 
rises and falls Avith it, the apparatus being so counterpoised as to yield to 
the slightest effort of the float as it rises and falls with the varying den- 
sity of the liquid in which it is immersed. The long arm of the lever 
actuated by the float terminates in a point or edge, which has a certain 
range of movement through an arc extending to some degrees above 
and below the horizontal. If a divided scale were placed behind this 
point, it might be so graduated as to enable an observer to read at any 
moment the density of the liquid in the tank. But as the object in view 
is not to indicate merely but to record, an additional mechanism is neces- 
sary to give motion to the registering dials. The principal of this me- 
chanism may be understood from the following general explanation : 
Immediately under the point of the lever just mentioned, and at a conve- 
nient distance, is the axis of the first of the wheels of the register : on 
this axis moves freely an arm which is capable of an oscillating motion, 
by which it is brought up at regular intervals against the point of the 
indicating lever, meeting this lever nearly at right angles. The point 
arrests its motion, and the arm is curved in such a maimer that this 
arrest takes place sooner when the point is depressed than when it is 
elevated. In this direction, therefore, the limit of the oscillation is vari- 
able; but in the opposite, it is constant. When the liquid in the tank 
which contains the hydrometer is pure water, the float is necessarily at 
its highest point, and the end of the indicating lever will accordingly be 
at its lowest. The adjustments are so made that, under these circum- 
stances, the oscillating arm has no liberty of oscillation at all. On the 
other hand, if the tank is filled with absolute alcohol, the float settles to 
its lowest point, and the oscillations of the arm attain their maximum. 
It only remains to contrive that these oscillations shall occur ar the exact 



VOLUMETER AND ALCOHOMETER. 



221 



intervals when a determinate quantity of liquid is delivered by the 
volumeter; and the connection between them and the registering appa- 
ratus is afterwards only a matter of mechanical detail, which requires 
no originality of invention. This end is attained by connecting with the 
axis of rotation of the volumeter a three-leaved cam, one leaf of which 
passes each time that a chamber of the volumeter is emptied of its con- 
tents. This cam, by suitable connections, determines the movement of 
the arm ; and at the same time, by means of a ratchet wheel of large 
diameter and fine teeth, which is fixed on the axis of the first of the 
register wheels, causes that wheel to turn through an arc equal to the 
angular movement of the arm. From what has been said it will be 
inferred that the curvature of the arm is such that its angular movement 
is proportional to the quantity of pure alcohol contained in the measured 
quantity of liquid at the density indicated at the moment by the position 
of the float. 

One additional provision,, rather important to the correctness of the 
indications of the hydrometer r has been attended to, which remains to 
be explained. A mixture of alcohol and water standing in a vessel at 
rest is liable to settle in strata of unequal density. It is indispensable 
to prevent such a condition of things from establishing itself in the tank 
which contains the float. The inventors have, therefore, provided a sys- 
tem of tubes for introducing the liquid into the tank and for withdraw- 
ing it, by means of which contrary upward and downward currents are 
propagated incessantly throughout the mass. The continual interming- 
ling of all the strata thus serves to maintain a density perfectly uniform. 

Fig. 68. 




Siemens and Halske's Volumeter. 



The foregoing description may be made, perhaps, somewhat more clear 
by referring to Fig. 68, which represents in vertical section the volumeter, 
the receiving chamber, the float, and the system of tubes and communi- 
cations designed to maintain the circulation. In this figure, H indicates 
the tube by which the liquid is introduced into the central chamber of 



222 



PARIS UNIVERSAL EXPOSITION. 



the volumeter. So soon as the level in this chamber reaches a the liquid 
overflows into the cavity I ; and until this cavity is filled the level is 
stationary. But when escape by this passage ceases to be possible, the 
level rises, and an overflow commences at a' into the cavity II on the left. 

The equilibrium of the vessel being thus disturbed, a rotation com- 
mences, and the chamber II descends. The point of efflux B, correspond- 
ing to the chamber I, being in this movement brought below the level of 
«, discharge commences from I, and continues until that chamber is 
emptied and the chamber II reaches the lowest place. The operation 
thus proceeds continuously. 

The system of circulation will be better understood by a mere inspec- 
tion of the portion of the figure on the right representing the receiving 
vessel, with the float P, and the system of distributing tubes, than by 
any description. The liquid introduced at G into the closed vessel T is 
divided into two portions, one of which ascends through c, overflows at 
K, and descends through d before entering the tank, AThile the other 
rises through e and enters at a higher point. Opposite currents are thus 
delivered both above and below the float, and the density is maintained 
uniform throughout the vessel. 

It must be said of this apparatus, as of nearly every thing which origi- 
nates with Mr. Siemens, that it is characterized by singular ingenuity. 
As a volumeter it seems to be perfect. Whether the sensitiveness and 
accuracy of the alcohometrical parts of it will prove to be equally satis- 
factory can only be determined experimentally. 



WATER METER OF MR. E. DUBOYS. 

Mr. E. Duboys, of Paris, exhibits a form of water meter which, for its 

simplicity and the 
necessary accura- 
cy of its measure- 
ments, must be 
well adapted to 
those cases in 
which great ra- 
pidity of flow is 
not important. It 
is also especially 
suited to the mea- 
surement of water 
under pressure. 
The construction 
can hardly be well 
explained without 
a figure. The wood 

Duboys's Water Meier— exterior. out annexed. Fig. 

69, presents an exterior view of this meter; and the interior is shown in 




DUBOYS'S WATER METER. 



223 



Fiff. 70. 




section in Fig. 70. The contrivance consists of two basin-shaped vessels 
applied to each other so as to enclose between them a cavity, which 
is divided by a flexible diaphragm of India-rubber. To the central part 
of this diaphragm is fixed a weight D with a double metallic disk, includ- 
ing between its parts the sheet of rubber, and adapted in form to the 
central bases of the cavity. 
This weight and its disk are- 
kept in position by a rod y 
which passes through the 
bases, and serves to guide 
the movement of the dia- 
phragm. At M and N are 
the apertures for the recep- 
tion and discharge of the 
water. It is seen, by the 
direction of the arrows in 
Fig. 70, that if water enters 
through the duct ME it will 
press upon the under surface 

Of the diaphragm aud disk, Duboys's Water Meter— interior. 

gradually filling the entire vessel, the water above the diaphragm mean- 
while escaping through FN, so that finally the flexible diaphragm will 
apply itself closely against the upper surface of the vessel. 

During this process the position of the apparatus is iuclined, as shown 
in Fig. 69 ; and when it is complete the weight D will be on the upper 
side and will cause that side to preponderate. The vessel being sus- 
pended on pivots will now tilt over, and by this movement will cut off 
the supply from the full side, at the same time opening the discharge 
valve for the escape of the water which it contains ; while on the other 
side, at the same moment, the contrary effect will be produced. Another 
charge will consequently now be admitted into the vessel, when the 
apparatus will tilt once more. 

It is evident that the preponderance of the upper side of the vessel 
will occur before the entire completion of the filling ; but were the posi- 
tion to be then immediately changed, the accuracy of the instrument as 
a meter could not be depended on. Provision is made against this in 
the following manner : P and Q are two troughs or grooves, undercut, 
so that the section presents the form of a bracket. At the extremities 
of the rod y are seen two square heads. These heads are too large to 
enter the groove except at its ends ; but the diameter of the rod is small 
enough to permit it to pass through in its whole length. When the 
apparatus tilts it is because the head, which is then lowest, falls beyond 
the extremity of the groove ; but as the rod enters the groove at one 
end and moves longitudinally, the head must traverse the whole length 
of the groove before it can escape. Although, therefore, the upper side 
of the vessel becomes the heaviest some time before the filling is com- 



224 PARIS UNIVERSAL EXPOSITION. 

plete, the head, which is held by the bracket, prevents any movement 
until the disk D comes fully into contact with the base of the cavity. 
This meter was in constant operation during the Exposition, and its 
performance appeared to be perfectly regular. 

CLEMENT'S WATER METER. 

Another form of meter exhibited by Mr. J. A. Clement, of Orleans, 
while more complicated than the last, and quite different in mechanical 
construction, presents a certain resemblance to that in the adoption 
of flexible membranes as the essential organs of its moving parts. 
Externally this meter exhibits the appearance of an upright cylinder, 
into which water is conducted at the base on one side, while the dis- 
charge takes place from the centre. Eive chambers are placed sym- 
metrically in the interior, into which the water is successively admitted. 
On the sides of these chambers toward the centre they are closed by 
flexible membranes of India-rubber, each being strengthened by a 
metallic plate, to which is attached a connecting rod designed to actuate 
a crank on a vertical axis in the centre. Thus there are five cranks all 
operating the same axis, but set at equal angles from each other in the 
horizontal projection. The central axis carries a compound or many- 
way stop-cock, which, as it turns under the pressure of the water, opens 
communication between each chamber and the water of supply, and also 
with the channel of discharge, successively. There being five in all, 
three are constantly discharging while the remaining two are filling. 

This meter operates fairly, the error of measurement being within the 
limit of one or two per cent. It was claimed for it that it is not liable 
to clog, in case the water carries solid matter in suspension ; a state- 
ment which, within certain limits, may be true ; but the discharge 
through a cock must impose the condition that there shall be nothing 
carried along in the nature of vegetable debris, which would be very 
likely to be jammed in the discharge orifices when closing. 

PAYTON'S METER FOR LIQUIDS. 

A meter was exhibited by the London Water-Meter Company, which 
they claim to be capable of delivering a larger quantity of water in a 
given time, in proportion to its size, than any other meter yet invented: 
and which they also guarantee to work equally well under all pressures. 
This meter somewhat suggests, in its construction, the rotary engines 
of Behrens, and of Pillnner & Hill, as it embraces within the same box 
two rotary parts which inosculate with each other. This resemblance 
will be recognized by inspecting the accompanying figure. 71 

But it differs from the machines just named, in the respect that the 
mass of the rotary parts is comparatively small : so that they displace 
but an insignificant amount of liquid compared with the total volume 
passing through. These rotary parts are shaped very much like the 
letter S, the arms of the letter having a cycloidal curvature such that. 



WATER METERS COCHRANE S. 



225 



in the revolution, the end of one runs in contact with the hollow of the 
other. This is what happens periodically in the Behrens engine, as 
heretofore described. The ends of the two Fig. 71. 

letter S rotaries which are not engaged with 
each other, are at the same time in contact 
with the outer wall of the enclosing box. 
It follows, from these statements, that there 
are extended junctures made by simple con- 
tact, on the tightness of which depends the 
prevention of the percolation of water 
through the instrument without being mea- 
sured. And these joints cannot be packed 
without creating a friction which will be 
equally prejudicial to their satisfactory per- 
formance. The whole of the lateral surfaces 
of the rotary apparatus must move freely 
over the plane surfaces of the ends of the 
box ; and the edges of the extremities of the Payton's Meter for Liquids. 
cycloids must move in the same manner over the whole cylindrical 
surface. Notwithstanding this apparent liability to leakage, the in- 
strument is asserted to perform without change of rate under all pres- 
sures. 




COCHRANE 7 S WATER METER. 

In the United States section was exhibited a water meter for measur- 
ing liquids flowing under pressure, which, from an error of classification, 
failed to come under the notice of the proper jury. Objects of this 
description were assigned in the programme of the imperial commis- 
sioners to Class 53. Cochrane's meter was entered in Class 12, where it 
was out of place, and was passed without attention. As it embraces 
all the important elements of a good meter, an attempt will be made to 
describe it here. The general appearance of the apparatus is shown in 
the figure, and is that of a cylindrical or cylindro-conical vessel, glazed 
for about one-half its altitude from the top, and constructed of metal 
below. The measurement is made by means of a vessel having some- 
what the form of a double scoop; this being divided in the middle by 
a partition, and balanced upon a pair of pivots in such a manner as 
to tilt alternately from the one side to the other, when by the flow of the 
water into the more elevated chamber the equilibrium is disturbed. 
Other inventors have employed this mode of measurement for liquids 
before 5 but as it requires that the measuring vessel shall not be immersed, 
it has not before been successfully applied to the case of water under 
pressure. Subjoined is the inventor's description, which is sufficiently 
explicit to require no addition. 

" Fig. 72 is a perspective view of the whole, the upper portion being 
of glass, to allow a view of the interior. The small sections show, on a 
15 I A 



226 



PARIS UNIVERSAL EXPOSITION. 



larger scale, the device for supplying air. Fig. 73 is a vertical section 
of the whole, as ordinarily constructed of cast-iron. 

Fig. 72. 



J n 


3SE 








s m 




i ( 


C 




Cochrane's Water Meter. 

" A is the pipe which supplies the water, and B a receiving and retard- 
ing vessel bolted upon the top of the main case C. This vessel serves as 
a kind of air chamber, and allows the water to fall gently into the cup 
below. D is a cock, through which the water is discharged, and E E is 
the surface of the water within: it being understood that the air above E 
is at the density required to equal the pressure due to the head of water. 



WATER METERS COCHRANE 7 S. 



227 



Fig. 73. 



This density is acquired in the first instance, simply by the rise of the 
surface E E, which thus compresses it. F is the rocking cup, and F' the 
partition therein. The cup being sup- 
ported on suitable bearings, its pivot 
is free to roll horizontally, to a slight 
extent, and thus to make the resist- 
ance a rolling rather than a sliding 
friction. G is a lever, mounted in 
the same frame with F, and imme- 
diately below it. It is slightly bent, 
as described, and immediately below 
it is a cross bar H, which regulates 
the extent to which either end of the 
lever G may, be depressed. 

"The centre of gravity is thus 
lower at either extremity of its mo- 
tion than at the middle of its vibra- 
tion ; and, in short, by well-known 
laws, the cup inclines with a certain 
uniform degree of force, to remain at 
either extreme of its motion. The 
water received from B through the ^ 
tube represented, accumulates on one <=m 
side of F' until its gravity is suffi- 
cient to overcome this tendency, 
when the cup rapidly tilts, and dis- 
charging its load on that side com- 
mences to receive an equal amount Cochrane's Water Meter— section. 

on the other. There is no resistance to the commencement of this rocking 
motion, except the gravity of the cup F and the rolling friction of the 
support, but towards the close of its motion it strikes the elevated end 
of the lever G, and depresses it. The devices for recording the strokes, 
and also for receiving the air, are worked from this lever G, by the aid 
of the rod I ; and both these operations, though necessarily communi- 
cating with the exterior of the case, are performed without the aid of a 
stuffing-box of any kind. 

a The tight joint required at the point where the motion is carried out 
through the case is obtained by the use of a kind of miniature slide valve, 
held to its seat by the pressure of the fluid within. A hollow projec- 
tion K extends upwards from the bottom into the interior of the case, 
A. Its interior communicates freely with the atmosphere, and its 
exterior is plane on one side and perforated as represented in Fig. 72, the 
perforations being covered by the small slide valve J. This slide valve 
is connected by the rod I to the lever G, and consequently moves ver- 
tically on the plane surface of K, at each movement of the latter. 

"The indicating mechanism is on the exterior of the case. It is simi- 
lar to that ordinarily employed on gas meters and the like, and carries 




228 PARIS UNIVERSAL EXPOSITION. 

several indexes, which work on the face of corresponding dials, as rep- 
resented by R, in Fig. 72. A ratchet wheel on the lowest and quickest 
shaft is operated by a pawl, which latter is connected to the work inside 
through the rod, L, which stands loosely enclosed in the interior of K, 
and is connected firmly to the slide valve J at the point K 7 , Fig. 72. 
This connection avoids the necessity for a stuffing-box. 

"When the valve J is in its lowest position, the water in its interior 
escapes through the aperture K'" and air from the interior of K flows 
in through the aperture J to supply its place. ^Now, when, by the 
means described, the valve J is raised to its highest position (that 
represented in the figures) the air freely escapes from the interior of J 
through the cavity J', and water finds access through side openings, 
imperfectly represented by dots, so as to flow in through J". At each 
movement of G, therefore, the indicating apparatus R shows that water 
has been discharged from the cup F, and also allows a quantity of air 
to rise in bubbles through the water. 

" The various pipes and cocks connected to the base of the case serve 
to draw water therefrom in the usual manner. They may discharge it 
directly at the cock from which it is seen flowing, or may lead it in the 
pipe represented to any distance, and the whole apparatus serves as an 
air chamber to regulate the motion of the water. 

"The device for receiving air is made a little larger than necessary, in 
order to insure a sufficient supply of that fluid within the case. Under 
ordinary circumstances, no harm can arise from a too great accumulation 
of air, as the aperture K", which obstructs the water, being higher than 
either of the other outlets, it simply follows that if the water surface 
becomes too low, small quantities of air instead of water are discharged 
through the cavity of the slide valve J, and as the density of the air escap- 
ing is greater than that introduced, the effect of this device is to reduce 
rather than increase the quantum of air in the case C ; thus there is no 
possibility of too much air accumulating, except under unusual circum- 
stances. In case the pressure in the street main should be suddenly 
diminished, in consequence of the burstin g of a pipe, or of an extraordinary 
quantity being drawn out in case of a fire in the vicinity, the air enclosed 
in C, by expanding, might force its way backward into the main. To 
avoid this, the reservoir B is arranged, as represented, so that it will 
receive and contain any air which might thus be displaced, and hold it 
ready for discharge into the case C again, so soon as the pressure is 
restored." 

IL—GAS METERS. 

The devices for measuring gas presented in the Exposition were al- 
most innumerable. There were very few, however, present which had 
not appeared in previous international expositions. Out of the great 
number, one or two seem to possess sufficient interest to deserve a cur- 
sory mention. One of these is the photometric gas meter of Mr. William 



GAS METERS. 229 

Suggs, of London; and another the constant level gas meter of the Lon- 
don Gas Meter Company. 

SUGGS'S PHOTOMETRIC GAS MEASURING APPARATUS. 

The object of this apparatus is to show not only the volume of gas 
which has been consumed at the end of a given time, but also the rate 
per hour or per minute at which the consumption is proceeding. This 
rate it is, of course, necessary to know when testing the quality of gas in 
regard to its power of illumination. Assuming as a unit a given light 
of constant intensity, the value of the gas light will be determined by 
comparing the brilliancy of its flame as produced in a burner of stand- 
ard form, when burning a determinate volume in an hour. The London 
unit of illumination, which is that generally used elsewhere, is the light 
of a sperm candle burning one hundred and twenty grains per hour. 
The apparatus of Mr. Suggs consists first of a gas meter which presents 
two conspicuous index hands, one of which revolves once in a minute, 
while the other makes a complete revolution during the passage through 
the meter of one-twelfth of a cubic foot of gas. The first of these move- 
ments, being maintained by clock work, is constant. The second, being 
dependent on the velocity of flow, or what is the same thing, on the rate 
of burning, may be varied by varying the freedom of discharge. Since 
one-twelfth of a cubic foot of gas passes with each revolution, if the 
revolution occupies one minute there will pass one cubic foot in twelve 
minutes or five cubic feet per hour. As the parliamentary statute re- 
quires that the gas furnished by the London companies shall possess an 
illuminating power, when burned at the rate of five cubic feet per hour, 
not inferior to that of fourteen sperm candles consuming each one hun- 
dred and twenty grains of the combustible in the same time, this appa- 
ratus, combined with a Leslie photometer, makes the application of the 
test very easy. The gas, before entering the meter, passes through a gov- 
ernor, which maintains the burning pressure uniform, however variable 
may be the pressure in the mains. It is therefore easy, by means of a stop- 
cock, to adjust the delivery so that the revolution of the volume index 
shall correspond exactly with that of the time index. A delicate bal- 
ance accompanies the apparatus, by which the consumption of the candle 
used for the purpose of comparison may be accurately ascertained ; so 
that the results of the experimental trial may be very expeditiously com- 
puted. This apparatus is designed of course for the use of gas-engin- 
eers, or for the officials whose duty it may be to test the quality of the 
gas furnished by the companies for the public consumption. 

CONSTANT LEVEL METER. 

The constant level meter manufactured by the London Gas Meter 
Company, is designed to prevent the inaccuracy of measurement to which 
the ordinary meters are liable, in consequence of the variability of the 
level of the water contained in the apparatus. Whenever the water is 



230 



PARIS UNIVERSAL EXPOSITION. 



too high, the error is against the consumer; when it is too low, the con- 
sumer is to a certain extent benefited. But from the construction of the 
instrument, for a given difference of level in excess or in deficiency, the 
first error exceeds the second very largely, and more largely as the dif- 
ference is greater. The common meter is never an accurate instrument, 
except when the water is exactly at that level to which the system of 
counters is originally adjusted. The water in the meter may be in- 
creased or diminished by design, but it naturally wastes by evaporation 
with the progress of time. As the meters are wholly under the control 
of the companies, they will naturally charge them with a view to save 
loss to themselves by the effect of this natural process; and the conse- 
quence is that the meter will generally contain an excess of water ; or 
that the time during which it is in excess will exceed that during which 
it is in deficiency. Yet if the periods of excess and deficiency were equal, 
the error on the whole would be in favor of the company. 

The constant level meter is, as its name implies, an instrument in 
which the level of the water is maintained at the same invariable height 
by an automatic action of the apparatus itself. Since loss by gradual 
evaporation is what is to be chiefly guarded against, the expedient 
naturally employed to produce the compensation is a float. This inven- 
tion is not the first in which afloat has been introduced for the same pur- 
pose ; but it is the first in 
which the compensation 
which it was the object of 
the expedient to secure has 
been effectually obtained. 
Some of the contrivances 
involving the use of the 
float have in fact been a 
source of greater inconve- 
nience than that which 
they were employed to 
remedy. The float in the 
present instance is of a 
semi-cylindrical form and 
is contained in a cylindrical 
chamber attached to and 
communicating with the 
meter. The semi-cylinder 
turns freely on a central 
axis, which coincides in po- 

Constant Level Meter. sitlOU with the SUl'taCC of 

the invariable water level. The annexed figure illustrates the con- 
struction and movement here described. Immediately above the water 
level, on one side of the chamber in its interior, is a small projecting tri- 
angular or wedge-shaped box, into which the gas enters by an orifice on 



t.iiK 




CONSTANT LEVEL GAS METER. 



the under side of the wedge, just at the water level. When there is no 
water at all in the meter, or very little, the float occupies naturally, by 
gravity, the lower half of the chamber ; but it carries on its plane side 
at the extremity which is thus brought immediately beneath the gas box 
just mentioned, a stopper, which enters into the opening which is the gas 
passage, closing it entirely and thus preventing further flow. If water 
is now introduced into the meter, the float, by its buoyancy, will gradu- 
ally turn round its axis, 
reopening the gas passage 
and permitting the flow to 
go on again. The float 
turns, because, in the po- 
sition in which it is ar- 
rested in its descent by 
the contact of its stopper 
with the gas box, its upper 
or plane surface is consid- 
erably inclined, owing to mm - t 
the length of the stopper. 
A greater portion of its 
bulk being then on .the 
side of the axis opposite 
to the gas box, the upward 
pressure on that side will 
preponderate. When the 
meter is full, the float will 
assume a position nearly 

Over the axis, but Still with Constant Level Meter. 

a small part immersed, since the gas box again arrests its movement 
before the plane side becomes horizontal. This position of the float 
is shown in the second illustrative figure. If an excess of water is 
introduced, it escapes immediately by overflow through a vertical pipe 
of which the upper extremity is exactly at the line of invariable water 
level. The escape of gas through this pipe may. be prevented by recurv- 
ing it at the lower extremity and filling the bend with water, or by allow- 
ing it to descend beneath the surface of water in another vessel. But 
as excess of water cannot be present except during the filling, it answers 
the purpose to leave the pipe open until the filling is complete, and then 
to close it securely. As the water wastes by evaporation, the float de- 
scends and immerses an increasing portion of its bulk, which is always 
exactly equal to the quantity of water which has disappeared. The level 
of the water thus remains always the same, and the rate of measurement 
of the meter is perfectly uniform. 




232 PARIS UNIVERSAL EXPOSITION. 

III.— BOILEE FEEDEES. 
riedel's feeder. 

Among the variety of contrivances for maintaining the water of steam- 
boilers at a uniform level which the Exposition embraced, there were 
two which belong to the class of meters as well as feeders, and which 
appear to be sufficiently novel to merit notice. One of these was an 
American invention exhibited by Mr. G. A. Eiedel, of Philadelphia. Its 
principal organ is a large receiver for the feed water, in the form of an 
ellipsoid with its longest axis vertical. This receiver communicates with 
the boiler by means of two pipes, one of which descends into the water 
of the boiler nearly to the bottom and terminates above at the bottom 
of the receiver, this latter being placed at a higher level ; while the other 
enters the boiler only to the proper, or rather minimum level, water line, 
and ascends to the top of the receiver. In the first-mentioned tube 
there is, beneath the water level in the boiler, a valve opening downward. 
This prevents the steam by its pressure from driving the water into the 
lower part of the receiver. Supposing the receiver to be full of water, 
and the water in the boiler to fall below the extremity of the shorter 
or gauge pipe, steam will enter this pipe and passing up to the top of 
the receiver will equilibrate the pressure upon the surfaces of the boiler 
and receiver water, so that the latter will flow into the boiler by its own 
gravity through the longer pipe. The water in the boiler being thus 
raised, the gauge pipe will be once more covered by it ; and in this con- 
dition of things water is prevented from ascending in this pipe as well 
as in the other by an automatic contrivance. If the receiver become 
quite or nearly exhausted, its weight will be diminished, and at the same 
time it will be necessary to draw a new supply from the source. This lat- 
ter object is accomplished by taking advantage of the diminished weight 
and of the fact that the steam which now occupies the place of the water 
which has been withdrawn, will by condensing form a vacuum within the 
receiver. This vessel is sustained by a balance beam carrying a kind of 
bracket resembling the bail of a kettle at one extremity, which embraces 
the receiver and lifts it by a pair of trunnions on its opposite sides. The 
other end of the balance beam carries a counterpoise. This beam is not 
pivoted at a fixed point in its length, but rests upon a roller in a verti- 
cal support, so that as the receiver rises, when, by the discharge of its 
water, it becomes too light to balance any longer the counterpoise, the 
relative length of the two arms of the lever varies with the movement. 
This movement takes place nevertheless about a fixed axis which is under 
the lever, and farther from the receiver than the roller support. This 
fixed axis is hollow throughout its length except at the central part. It 
is therefore in effect divided in the middle point by a permanent parti- 
tion. One end of this tube communicates with the long or deep tube 
in the boiler, and the other with the short or gauge tube. And the con- 



BOILER FEEDERS— RIEDEL'S HOUGET & TESTON's. 233 

tinuation of these tubes to the receiver, as above described, takes place 
through the medium of these two opposite halves of the axis tube. The 
connections between the axis and the receiver, whereby this vessel is 
forcibly compelled to describe an arc having- its centre in this axis, are, in 
fact, the tubes above described which provide for the circulation of the 
water and steam. They are therefore constructed of sufficient strength 
to give rigidity to the system ; and, as will be inferred from the descrip- 
tion, their direction is horizontal ; so that in leaving the receiver they 
make a right angle. 

This being understood, let it be supposed that the receiver has dis- 
charged its water into the boiler and is full of steam. The counterpoise 
now predominates and the receiver rises. In rising it acts upon two 
valves, one of which by closing cuts off communication between the 
boiler and the receiver through the gauge pipe, while the other opens a 
communication between the receiver and the source of water supply. 
The vacuum created by the condensation of the vapor is immediately 
filled by the water, which, giving once more the predominance of weight 
to the receiver, causes the system to tilt back into its original position. 
Xhe ingenuity of the arrangement of parts by which the lever arm sus- 
taining the receiver is automatically lengthened and shortened in the 
successive oscillatory movements appears in this, that when the receiver 
is filling, the arm which suspends it is at its minimum of length, so that 
it does not acquire weight enough to overcome the preponderance of the 
counterpoise until it is entirely full. On the other hand, when it has 
resumed the position which is determined by its own preponderance, the 
length of the arm is maximum, and it is impossible for the counterpoise 
to prevail until it is once more fully discharged. 

This apparatus serves admirably for feeding fixed boilers. As it is 
dependent on the action of gravity, it would not answer for engines on 
shipboard. One advantage attendant on it is, that, by the addition of a 
system of register dials, the quantity of water supplied in a given time 
may be measured, and therefore an exact account may be kept of the 
quantity of steam made. 

HOUGET & TESTON'S FEEDER. 

This contrivance, which serves equally, like the last, as a feeder and a 
meter, cannot be well described without the assistance of a diagram. It 
is shown in section in the accompanying figure 76. In the interior of the 
vessel are seen two floats, a large one D and a smaller one D'. The 
float D, in the condition of things shown, is maintained in its position, 
notwithstanding the rising of the level of the water, by the lever E, to 
which it is attached, and which is checked by the catch at the heel of 
the lever E", which detains it at the point I. These arrangements will 
be more clearly understood by reference to the enlarged Fig. 77. The 
lever E acts upon another lever by a connection at E, which second lever, 
in the position represented, lifts- the valve K, being pivoted at a point 



234 



PAEIS UNIVERSAL EXPOSITION. 



not lettered, above E". This same lever is capable also, when lifted by 
the lever E, of opening the valve L, and of closing the little valve not 
lettered, further to the right. This last valve is an air escape and 



Fig-. 76. 




wmtP 




Houcret & Testoirs Feeder. 

remains open while the feeder is filling, to prevent a back pressure from 
the confined air. The valve K, which is lifted in the position shown, 
admits water by natural descent from a source higher than the feeder. 
or as thrown in by a force pump. As the water rises it lifts the small 
float D', which is guided by the vertical rod E"'. VThen the float LV 
reaches the lever E ;/ it releases the extremity of the lever E : and the 
large float D being now completely immersed, ascends with great force, 
closing the valve K and the small air-escape valve, and at the same time 
opening the valve L. The valve L opens communication with the steam 
of the boiler, and thus equality of pressure is established on the surface 
of the water in both boiler and feeder. If now the valve O is open at 
the top of the tube communicating between the boiler and the bottom 



BOILER FEEDERS HOUGET & TESTON S. 



235 



of the feeder, the water will descend freely, lifting the light valve M, 
which is placed there to prevent an ascent of the water from the boiler 
into the feeder, in case O should be open when the feeder is in process 
of filling. 

As the water falls in the feeder the float D will lose its buoyancy, so 
that if free to descend it would close the valve L and open the valve K, 




Houget & Teston's Feeder — enlarged view of upper part. 

in consequence of which the feeding process would be arrested. In 
order to prevent this a catch is fixed to a lever connected with the ver- 
tical rod W" which hooks on to a stud at the extremity I of the lever E, 
and prevents the descent of that lever. The float D consequently re- 
mains suspended until the small float D' has reached in its descent the 
cross-pin near the bottom of the rod W". By the time that so much of 
the water of the feeder as can pass out through M has made its escape, 
the weight of D', which will then be nearly uncovered by the water, will 
be sufficient to operate on the lever by which the rod W" is suspended, 
releasing the stud I in the lever E from the catch which detains it, and 
allowing the float D to fall. With the fall of this float the steam valve 
L is closed, and the water valve K is opened. The air-escape valve is 
also opened at the same time. The process of filling then recommences, 
and goes on as before. 

The opening and closing of the valve O is determined by the float P, 
which is counterpoised while the water is sufficiently high ; but when, 
by the descent of the level, P is left too far uncovered, its weight pre- 



236 PARIS UNIVERSAL EXPOSITION. 

dominates and tlie valve opens. The valve may be fastened permanently 
down by a screw entering from above. The counter is placed on the top 
of the feeder. Its position is given in outline on the right. There is 
much ingenuity in this contrivance, and for fixed boilers it must be very 
useful. 



CHAPTER VIII. 

MACHINES AND MECHANICAL APPARATUS DE- 
SIGNED FOR SPECIAL PURPOSES. 

Multiplicity of interesting objects in this class— Machinery from the United 
States— Sellers's planing machine — Machines for special purposes— Arm- 
strong's dovetailing machine — Zimmermann's-Ganz's-Whitney's gauge-lathe 
— Perrin's band saw — Machines for making barrels, pencils, nails, hinges, 
and for dressing millstones— Brick-making machines— Machines for cut- 
ting tobacco, for making shoes, corsets, chenille, and for folding paper — 
Cutting sugar— Washing and corking bottles — Miscellaneous inventions — 
Electrical detectors— Cloth-drying— Safety brakes— Mechanical broom- 
Automatic grain weigher — Improved millstones. , 

INTEODUCTOEY OBSEEVATIONS. 

The applications of machinery to the arts of life are so various, that 
an exhaustive report upon the objects present in a great exposition which 
properly arrange themselves under the title placed at the head of the 
present chapter, would be a very arduous undertaking, and would 
occupy a very large space. Nor is the preparation of a partial report 
an undertaking without its difficulty ; since, amid the multiplicity of 
interesting objects offered to his choice, the reporter is often embar- 
rassed which to select. The present writer is to a certain extent relieved 
of this embarrassment, by the consideration that it will be the province 
of other committees to take account of the machinery and processes 
employed in some of the most important departments of industry ; while 
his own more general task is rather to notice only such as might be 
likely to escape their attention. 

The notices embraced in the present chapter relate to such objects of 
the class thus indicated as excited at the time of their examination the 
strongest interest in the mind of the writer. It does not follow that 
there were not many other things equally worthy of record ; but in the 
necessity of choice an individual must be limited to the range of his 
own observation and guided by such judgment as his knowledge of the 
matters observed enables him to form. It would have been well if the 
study of these very diversified and miscellaneous matters had been 
intrusted to a mechanical engineer or expert by profession ; since per- 
sonal experience and familiarity with industrial operations are surer 
guides to a correct appreciation of such things than any theoretic 
knowledge can be. In view of this fact the present reporter has sought 



238 PARIS UNIVERSAL EXPOSITION. 

as far as possible the assistance of practical men, has availed himself 
of the descriptions (where they were obtainable) given by inventors 
themselves, and has borrowed to some extent from the notices of 
reporters to the different journals of practical science. Many of these 
journals were represented at the Exposition ; but none of them more 
persistently throughout the continuance of the display, and none of 
them with more ability and judicious discrimination, than the London 
Engineering. The volume of that journal for 1867, in itself alone, 
embraces a more comprehensive and more satisfactory review of the 
Exposition, especially so far as Groups Yand YI are concerned, than any 
official reports which have yet appeared. Its descriptions of the most 
important machines, instruments, processes, and products exhibited were 
elaborate, and its illustrations, which were given with profusion, were 
clear in their details and were admirably executed. 

In the notices which follow, it has been no part of the design to enter 
into minute description. The character of each invention, the uses it 
may subserve, and the extent to which it promises to be, or has already 
proved itself to be, an improvement on previously existing forms of 
industry, or a contribution to productive power, are all which the objects 
of this report require, or which its limits will allow. 

MACHINERY PROM THE UNITED STATES. 

To an American it was exceedingly interesting and gratifying to 
observe, that while the space allotted to his country was actually small, 
the amount of ingenuity and originality which it embraced, especially 
as it respects the forms of machinery applied to the useful arts, was 
relatively very great. And while it was manifest to any one acquainted 
with the existing state of mechanical industry in the United States, 
that the country was very inadequately represented, it was equally 
obvious that, so far as it was represented at all, it was well represented. 
It was indeed worthy of notice, in reading the sketches of the Exposi- 
tion contributed to the leading journals of the day, as well as to those 
devoted specially to the interests of industry, by their regular cor- 
respondents, how large an amount of attention was given to American 
machinery. 

The number of American exhibitors of machine tools was quite 
limited compared with those of France and England, their principal 
competitors; but among the objects presented by these few were some 
of the most efficient of their kind and of the most original in their con- 
struction, which the Exposition embraced. Those of Messrs. Sellers, of 
Philadelphia, Brown & Sharpe, of Providence, and Bement & Dough- 
erty, of Philadelphia, for working in metal: and those of Messrs. 
Eogers & Co., of Norwich ; of Whitney, of Wirichendon, Mass.. and of 
Cool, Ferguson '& Co., of Glen's Falls, were especially commended. 
The study of this class of machines has been intrusted to another ; but 



MACHINE TOOLS. 239 

it may be permitted here to mention the compliment paid to Mr. Sellers 
by the jury, of the class, who pronounced, his magnificent planing machine 
to be, "as well for its dimensions as for the novelty of its construction, 
the most important in the Exposition." Of its moving parts they add, 
" the guidance is perfect, and most of its automatic transmissions are 
new and very efficacious." And of the other machines presented by the 
same exhibitor, the acute observer who contributed the contemporaneous 
notices of the machinery of the Exposition to the London Engineering 
spoke at the same time in the following terms of high commendation : 
"The designs present a great amount of originality, and some of these 
machines, particularly the bolt-screwing machine, have found universal 
favor in European workshops. The other tools exhibited in Paris pre- 
sent a similar character. We note a small planing machine brought out 
by Mr. Sellers in 1860, and patented in this country, having its gearing 
from the driving pulley direct by a single pair of bevel wheels working a 
worm, the shaft of which is placed at an angle with the line of motion 
of the planing machine table, and working into a rack beneath. The 
self-acting motion for changing the strap for the return motion is placed 
at one side in a very compact form, and the tool box has a self-acting 
motion for lifting the tool oft' its work during the return stroke. Mr. Sel- 
ler s's lathes are fitted with sliding carriages, having no compound slide- 
rest on the top of the carriage, but simply a cross-slide only on the top 
of the carriage itself. This necessitates the movement of the whole 
carriage by hand in setting the tool to its work, but it saves expense and 
simplifies the machine. The carriage has a sliding movement by rack 
and pinion, which is obtained from the fast headstock by means of fric- 
tional gearing between adjustable revolving disks. By changing the 
relative position of these friction plates it is possible to vary the rate of 
feed given to the sliding carriage with a constant speed of revolutions 
given to the mandril. The disks are pressed against each other by short 
spiral springs, and appear to afford a very handy method of adjusting 
the cut according to the requirements of the material operated upon. 
The smaller lathe of Mr. Sellers shows an adjustable tool-holder, which 
allows the turning tool to be set at different angles to the work, as is 
occasionally, but not very often, required. There are also adjustable 
stops provided for cross-cutting up to a given depth. Each of Mr. 
Sellers's machines has a box for storing tools in some part of its hollow 
framing. In the designs it would be difficult to point out any precise 
English original ; there is nothing but the general mode of distributing 
the material, and the manner in which most of the details are con- 
structed, which shows Mr. Sellers's really intimate acquaintance with 
English practice. In every other respect there is a decided originality 
about these machines, placing them upon a totally different level from 
mere imitations, and giving in many instances to Mr. Sellers the credit 
of having originated some of the most useful specialties of tools now 
to be found in English workshops." 



240 



PAEIS UNIVERSAL EXPOSITION. 



I.—MACHIKES FOE SPECIAL PUEPOSES. 



ARMSTRONG'S DOVETAILING MACHINE. 

The Exposition contained four or five machines, all more or less 
ingenious, for performing the rather difficult work of making dovetail 
joints. Of these, the most expeditious in its operation, and as satisfac- 
tory as any in performance, was the American machine bearing the 
Fig-. 78. name of the patentee, 

Armstrong, of ^S~ew 
York. Without com- 
plete drawings it 
would be impossible 
to convey an idea of 
the action of the ma- 
chine in all respects ; 
but the essential and 
most important part 
is shown in the figure 
annexed. It will be 
seen that there are 
two disks mounted on 
axes inclined to each 
other, as well as to the 
main driving-shaft, 

Armstrong's Dovetailing Machine. and revolving at the 

same speed, the one being inclined to the right and the other to the 
left, the motion being transmitted from the first to the second disk 
by means of bevel wheels cast on their inner surfaces. Each disk 
has on its outer circumference a spiral groove making one complete 
turn, into which is fitted a saw composed of segments, so arranged 
as in one complete revolution to give both the longitudinal and trans- 
verse cut necessary to finish a dovetail, one half being made by one 
disk and the other half by the other. The leading portion of the saw 
is composed of segments similar to those that could be cut from an 
ordinary fine-pitched circular saw, while to produce the transverse 
cut after the longitudinal one is finished the segments assume the 
form shown in the engraving, from an inspection of which the arrange- 
ment will be better understood than it could be from description. The 
saw which makes the cross-cut will be seen, in fact, to be placed 
like a belt or hoop on the circumference of the plane circular saw 
plate which forms the direct cut, and to widen gradually out to the 
breadth required for the cut. This hoop saw is not set at right angles 
to the plane saw, but at the bevel which corresponds to the angle of the 
joint. The segments which form the saws are held in their places by 
means of cast-iron cheek-plates held on by set screws with square heads. 
and in about one minute the attendant on the machine could change all 




DOVETAILING MACHINE. 241 

the segments and replace tliem by others having a liner or coarser 
pitch of teeth if desired. To prevent the saws from splintering the wood 
on its under side, a longitudinal shallow cut is made by a knife-edge at 
the bottom of the dovetail before the helical saws operate on the wood; 
this is a most important point, and without it good work cannot be pro- 
duced. The engraving above illustrates only the mode of forming one 
part of the dovetail. At the back of the machine provision is made for 
cutting the other part with equal expedition. An arrangement is also 
provided for raising the table so that the dovetailing can be done on a 
bevel if desired. The attendant was all day long besieged by crowds 
anxious to see this machine at work, and certainly he showed great 
patience in altering his machine to convince the sceptical of its wonder- 
ful scope and accuracy. 

zimmermann's dovetailing machine. 

Mr. J. Zimmermann, of Chemnitz, Prussia, exhibited a dovetailing 
machine in which three revolving cutters, having a form corresponding 
to that of the dovetail recess to be made, operate to cut simultaneously 
three recesses in the edge of the wood. The wood itself is placed on a 
horizontal table and moved downward before the cutters by means of a 
vertical slide to which the table is fixed. The three cuts being com- 
pleted the slide has a horizontal motion sufficiently large to bring a fresh 
portion of the wood before the cutters, when the operation is repeated. 
For cutting the counterpart of these dovetails the same machine is 
employed, with plain revolving disks or cutters, the table being then 
placed in an inclined position, so that the vertical slide, in carrying the 
wood against the cutter, produces a parallel cut inclined in one direction ; 
and at a second operation, for which the table is placed in an opposite 
inclination, the second bevel is produced. The machine has the advan- 
tage of being small and compact, and cheaper than some other dove- 
tailing machines exhibited. Its only drawback is the multiplicity of 
changes required in setting the machine for doing the different parts of 
one operation before the work can be completed. 

GANZ'S DOVETAILING MACHINE. 

Still another machine for the same purpose was exhibited by Mr. A. 
Ganz, of Ofen, in Hungary. The following description may convey 
some idea of its operation, although without figures it is difficult to make 
it perfectly clear. 

The novelty in this machine consists in its operating simultaneously 
upon the two wooden planks or boards which are to be dovetailed 
together, and in its producing the kinds of dovetails which form the 
counterparts of each other by the same action of one set of cutters. 
The machine consists of a pair of revolving disks, each fitted with a 
series of plain cutters at their circumferences, and geared together by 
means of bevel wheels, so as to revolve in two planes which form the 
16 i A 



242 PAEIS UNIVERSAL EXPOSITION. 

same angle as that intended to be given to the projecting dovetails. 
The board in which the recessed cuts are to be made, rests upon a hori- 
zontal bed, on which it slides immediately in front of the cutters. The 
two sets of revolving cutters are set sufficiently far apart to enclose 
between their planes of motion the width of two dovetails, so that one 
cuts the right side of one projection while the other produces the left 
side of the next following. In the next stroke or cut the board is moved 
forward with its carriage by means of a screw to the exact pitch of the 
dovetails, and a repetition of the same operation completes the second 
side of the projection last made, so that at each cut one dovetail is 
completed and the next following cut out on one side. The revolving 
tool advances through the wood vertically downward, or rather in an 
arc of a circle described by it round a fixed and rather distant centre. 
In order to effect this movement the cutters are mounted, not in a frame 
incapable of movement, but at the extremities of arms which are hinged 
at the opposite extremities, so that by the revolution of a cam the knife 
ends can be raised or depressed. Each revolution of the cam corres- 
ponds to one down- stroke of the two arms, or to one cut through the 
board. At the extreme end of the cut a fixed tool for cross-cutting is 
placed, which, in the descent of the cutter frames, clears the bottom of 
the dovetail and produces a smooth surface at that place. These move- 
ments complete the operations of the machine, but they are at the same 
time made use of in a very ingenious manner to produce the correspond- 
ing dovetails in the other board which is to be fitted to the first. This 
second board is fixed to the machine in a vertical position: that is, at a 
right angle to the board first mentioned, and in the same position in 
which it is to be fitted to the latter. In this position it is obvious that 
the revolving cutters make grooves into the second board exactly corres- 
ponding to the projections left on the first, and the two boards being 
once properly set against each other, the same cut of the revolving tools 
will produce the dovetails on the first and the corresponding grooves 
on the second board. The machine at the Paris Exhibition is the first of 
that kind made by Mr. Ganz, and is capable of being improved in some 
of its details, but as a whole it is well designed, and its mode of action 
is very ingeniously contrived. 

WHITNEY'S GAUGE EATHE. 

This is another American machine which attracted much attention at 
the Exposition for its effectiveness and its originality. It is the inven- 
tion of Mr. Baxter D. Whitney, of Winchendon, Massachusetts, and is 
designed to turn out chair rounds, banister columns, and all similar 
objects in which the cylindrical form is modified by contraction or enlarge- 
ment of diameter, the formation of beads, &c., so as to present curves 
or broken lines in its contour. Without the aid of drawings, it is diffi- 
cult to make the construction intelligible in its details, but the general 
mode of its operation maybe understood from the following explanation: 



Whitney's gauge lathe. 243 

The rough piece of wood which is to be turned is placed between two 
centres, as usual. The centre next the driving pulley is formed in the 
manner of a serrated disk, so as to grip the end of the piece to be turned, 
and the other centre is formed with a central raised point and slightly 
raised rim all round the small disk which constitutes the end of the 
spindle. This centre is advanced or withdrawn by a screw and hand- 
wheel as usual. The wood in the lathe, supposing that it is to be turned 
to a figure of undulating or otherwise varied outline, is first brought to 
the form of a regular cylinder; and this is done by means of a fixed 
chisel in a slide rest, which is advanced on its bed in the same maimer 
as any common slide rest, by means of a screw driven by a pulley. The 
slide rest, however, has two chisels in it, one of which is intended, as just 
stated, to reduce the wood to the form of a uniform cylinder, while the 
office of the other is to cut away the portions of the cylinder which must 
be removed in order to produce the varied outline which the design 
requires. This chisel performs its function in a comparatively rough 
way; the finish of the work being accomplished by a supplementary 
device presently to be exjjlained. The manner in which this chisel is 
made to do its work will be understood when it is stated that the chisel- 
holder is hinged, and that a foot firmly connected with it rests on an 
iron rail or gauge, which is cut to the contour which the wood is to have. 
As the slide rest advances this foot rises on the swells and sinks into 
the depressions of the gauge ; and the tool-holder, with its tool, rises 
and sinks with it, and thus transfers to the wood the precise contour of 
the gauge. There cannot, it is obvious, be a complete finish in this way, 
especially where there are sharp angles in the outline required. The 
steady advance of the chisel in the longitudinal direction would prevent 
the exact reproduction of these, and they would, moreover, interfere with 
the smooth sliding of the foot. 

The final finish is therefore very ingeniously given by means of another 
tool, which is now to be described. Immediately behind the wood in 
the lathe is a vertical frame, which has a free motion up and down in 
guides ; and to this frame is attached, at an angle of about thirty degrees 
to the axis of the lathe, a long knife with its cutting edge downward, 
extending the whole length of the piece of wood to be turned. This 
knife is moulded or corrugated also to the form of the design to be exe- 
cuted ; so that, if an orthographic projection of it should be made on a 
horizontal plane, the projection of the edge would be the exact outline 
which the pillar, when finally completed, is to present. low, if there 
were no sliding chisels, it is evident from this statement that the knife 
here described, supposing it to be brought downward on the wood as it 
turns in the lathe, might, provided it were strong enough, and provided 
that the wood were yielding enough, cut out the required column at once 
from the rough block. But as this operation would in general exact 
some force, the result would not probably be very satisfactory. It is 
preferable to bring the figure very nearly to the required shape and 



244 PARIS UNIVERSAL EXPOSITION. 

dimensions before bringing- clown this guillotine knife: and then this, 
having little to do but to smooth the surface, will produce a neat finish 
at very little expenditure of force. 

One important part of the mechanism, which has not been thus far 
mentioned, must not be overlooked. The slide rest carries an arm and 
circular gauge, this latter having the exact diameter of the cylinder 
turned by the fixed chisel, and intended to follow over the wood as fast 
as it is turned to the cylindrical form, in order to steady it during the 
subsequent operations. During the process of fixing the wood in the 
lathe, this gauge admits of being run back over the movable centre out 
of the way. 

It remains to be explained in what manner the diagonal guillotine knife 
is brought into action. The frame to which the knife is attached is coun- 
terpoised in such a manner that it requires but little force to move it 
either up or down. It has also a diagonal bar at a lower level than the 
knife but parallel to the latter, which carries a projecting flange pre- 
sented toward the slide rest. A notch in the rest, or in an arm con- 
nected with it, is adapted to this flange ; and as the rest moves along 
horizontally while the flange is inclined, the knife is brought gradually 
down. Thus it may happen that upon different parts of the same column , 
the fixed chisel may be reducing the rough surface of the original 
wood, the movable chisel may be doing the heavy work of reduction to 
the required contour, and the descending knife tbe light work of finish- 
ing, all at the same time. Of course a different knife and gauge rail 
will be required for every different pattern of pillar. But the other 
parts of the mechanism will remain without alteration, whatever bulg- 
ings or mouldings are employed. For the purpose for which it is intended 
nothing can be more rapid and efficient than this lathe, and a similar 
device might with advantage be introduced to form the bulging pillars 
of balustrades in stone in all cases where a large number of them is 
required. 

Beside this lathe Mr. Whitney exhibited several other machines for 
working in wood, which were complimented by the discriminating 
reporter for the London Engineering, as being "all novel in their prin- 
ciples of construction, original and elegant in their design, excellent in 
workmanship, and perfectly successful in their performance." He adds : 
" They may be considered as model types for study and imitation, and 
they have earned the approval of every competent visitor to the Exhi- 
bition." 

And in regard to one point of special interest he goes on to observe : 
" There is one important feature in the construction of these machines 
to which Ave are desirous of drawing attention, as it is a question 
of principle rather than one of detail. Whitney's machines are con- 
structed with a remarkable economy in weight. The frames are in 
appearance and in reality considerably lighter than anything that could 
be designed by our first-class makers of wood-working machinery : and 



245 

yet these machines show no trace of vibration in working and are proven 
to be of ample strength by their performance. We have heretofore 
noticed the fact that the modern tendency in the construction of wood- 
working tools is to reduce the dead weights ; and we are glad to find in 
Mr. Whitney's machines a practical illustration how much more is yet to 
be done in this direction, an illustration which we believe will not be 
lost even upon those among our machinists who are the most anxious to 
insure solidity and strength by the profuse application of massive and 
heavy castings. With scientific designs and excellence of workman- 
ship, we have no necessity for the application of heavy masses for 
machinery which runs at such very high speeds, and has so little direct 
strain upon its working parts as the generality of wood- working tools." 
This critic pays a compliment to our country in general in respect to 
this branch of industry, in saying that European engineers had looked 
forward to the exhibition of wood-working machinery in the American 
department with unusual interest, regarding America as " the natural 
home and native land of this kind of machinery; 7 ' since the United 
States had furnished the first models of the most important wood-work 
ing tools in general use in Europe ; and since these tools, however modi- 
fied in details, still preserve everywhere their distinctive principles and 
main features of construction, "just as they were transmitted to us 
across the Atlantic." He says, indeed, that even yet British and con- 
tinental artisans are accustomed, whenever a new desideratum in 
wood-working machinery makes itself felt, to look to America to fur- 
nish the desired relief; and that they even continue to be occasionally 
surprised by the appearance of a new tool from the u States" before they 
are aware that they want it ; though they very soon learn to appreciate 
the value of the present after giving it atrial. 

perin's band saw. 

The substitution of the circular for the reciprocating saw was a very 
important step of improvement. It introduced a considerable economy 
of the force employed, and a still larger economy of time. The recipro- 
cating saw occupies as much time in rising as in descending, and is 
therefore effective only during one-half the period of the operation. But 
the continuous action of the circular saw is attended with the additional 
advantages that it can be run at a higher rate of speed than is possible 
for the older form, and that it admits of a heavier feed on account of the 
steadiness and regularity of the continuous cut. 

These advantages have been secured for the saw with a straight edge, 
by Mr. Perin, of Paris, by giving to the tool the form of a band running 
over pulleys of diameter sufficiently large to allow the material to be 
operated upon to meet the saw on the descending side, without being inter- 
fered with by the part which is rising. The saw must of course be made 
of very flexible steel, and it is therefore comparatively thin. On its first 
introduction some disadvantage was experienced from this circumstance, 



246 PAKIS UNIVERSAL EXPOSITION. 

on account of its unsteadiness. This, however, has "been overcome by 
the simple expedient of placing a fixed guide, which is nothing but a 
piece of wood having a slit in it equal to the thickness of the saw. 
immediately above the material which is to be cut. A similar guide is 
also usually placed below. 

These band saws are constructed of various sizes, some of them suffi- 
ciently large to cut heavy timber. But the most interesting forms are 
those of which the breadth is hardly greater than that of a watch spring. 
These are used to cut out scroll work, a function which they perform, 
whatever may be the degree of delicacy or intricacy of pattern, with sur- 
prising rapidity. Such saws were exhibited in both the British and the 
French sections of the Exx>osition. and were constantly occupied in cut- 
ting out fanciful patterns for the gratification of visitors. Scrolls and spi- 
rals were cut out of blocks of bard mahogany four or five inches in 
depth, with very sharp curves, and of a thickness not exceeding that of 
very thin card-board. The initials of the names of visitors were cut with 
great rapidity, in a very graceful script, and objects of this kind seemed 
to be especially popular. The object and the matrix are equally perfect : 
and owing to the very slight thickness of the tool, the one fits neatly into 
the other and presents the pattern in relief. The band saw in this form 
is thus a very important addition to the resources of the ornamental 
worker m wood: surpassing immensely in precision, as well as in rapidity 
of execution, any similar tool used in the hand. It is destined, doubt- 
less, to come into very extensive use. 

"When first introduced, this tool was not an immediate success. On 
account of the inequality of temper, or want of uniformity of quality of 
the steel, fractures were frequent. The welding of the two extremities 
which was necessary in forming the band, however carefully performed, 
presented always a point of insecurity. Experience has. however, sug- 
gested means of overcoming these difficulties, and at present fractures 
are of rare occurrence. It is considered, nevertheless, to be a judicious 
precaution against injury from such possible accidents, to surround the 
saw with a wooden box or shield, at least as high as the head of the 
workman. The pulleys are covered on their circumferences with leather. 
and the necessary tension is produced by adjusting screws, by which the 
distance of the two pulleys from each other can be varied. Some con- 
structors. however, employ springs, or even weights, to maintain the 
tension. 

In the British department the machine exhibited was provided with 
a table or bed susceptible of being inclined, so as to vary the angle at 
which the material is presented to the saw. The same object could be 
secured, of course, but less conveniently, by inclining the material upon 
a horizontal bed. and blocking it up in such a position. Some of the 
French constructors have even contrived to make the position of the saw 
itself variable, giving it at pleasure a vertical or inclined position while 
the material remains undisturbed upon a horizontal bed. Either of these 



MACHINES FOR MAKING BARRELS AND PENCILS. 247 

two expedients contributes very much to increase the usefulness of the 
machine. The velocity with which the saw runs is very great, being as 
high as fifty feet per second; yet its motion is so steady and silent that, 
to the spectator, especially in the case of the narrow scroll saws, it hardly 
seems to be moving at all. It needs only to be added that the feed is 
not intermittent, as in the case of ordinary saws, but is uniform and 
smooth, like the motion of the saw itself. 

BARREL-MAKING MACHINERY. 

Another of the very original contributions of the United States to the 
machinery department of the Exposition consisted of the machines, three 
in number, exhibited by Messrs. Cool, Ferguson & Co., of Glen's Falls, 
New York, for making casks and barrels. The three operations performed 
by these machines are — first, the cutting of the staves to the required 
length, finishing the ends, and providing them with the necessary groove 
for the introduction of the head ; secondly, the finishing of the sides of 
the staves, for which purpose a number are firmly held together, and 
subjected to the operation all at the same time ; and finally, the forma- 
tion of the heads to the proper size and figure, and with edges suitably 
prepared to enter the grooves in the ends of the staves. The advan- 
tages afforded by these machines over the hand manufacture of casks, 
are not simply economy of expenditure and saving of time. The article 
produced is much better than the hand-made article. It is easy, indeed, 
to perceive that the perfect uniformity of parts secured by the machine, 
and the perfect similarity of joints, must greatly improve the accuracy 
of fitting, and render the cask* more solid, less liable to leak, and more 
durable than can be the case where, as often happens, the iinperfection 
of workmanship is only masked or concealed by an excessive strain upon 
the hoops. The machines exhibited found, it is said, a prompt sale in 
France, having been purchased for the use of an establishment manu- 
facturing Portland cement. 

PENCIL-MAKING MACHINE. 

The pencil-making machine of C. B. Eogers & Co., of Norwich, Con- 
necticut, deserves mention for its ingenious adaptation to the object for 
which it is intended. This machine performs all the successive opera- 
tions required in this manufacture with the utmost precision ; commenc- 
ing with planing the wood, cutting subsequently the grooves for the lead, 
and finally rounding and finishing off the pencil and turning it out 
complete. 

The pencils are made six at a time. The machine is first used for 
planing and squaring small boards, each representing six pencils, which 
are to be cut from it. One set of these square boards is of a sufficient 
thickness to receive the groove for leading, and the other set is thinner, 
so as to be glued over the leaded board and to complete the pencil. The 
grooving is done by the same machine, which is fitted with a pair of 



248 PARIS UNIVERSAL EXPOSITION. 

revolving cutters. There are six projections on tlie cutters, which pro- 
duce the six parallel grooves. The lead is then inserted into the grooves, 
and the thin hoard glued over the whole, so that the six pencils are now 
represented by two square boards containing six bars of graphitic sub- 
stance between them. The cutters of the machine are now again ex- 
changed for one with six half-round grooves, which forms the six round 
pencils, when the board is passed through, first with its upper, then with 
its lower surface next the cutters. The cutters are made in halves of a 
complete cylinder, so as to facilitate their being properly sharpened; 
they obtain their clearance by being set eccentric to the axis of the 
rotating spindle which contains them. The exchange of cutters for the 
successive operations just described is intended to take place only after 
a large quantity of work has gone through one of the respective stages 
of manufacture ; and for large works it would be necessary to provide 
several machines, each used only for one distinct part of the process. 

This machine attracted much attention and admiration ou the part of 
visitors; and for its great merit, together with that of his other excel- 
lent machines for wood-working, Mr. Sogers was awarded by the jury 
the honorable recompense of a gold medal. 

WICKEKSHAZtf'S NAIL MACHINE. 

One of the most interesting and novel of the machines for special pur- 
poses which the Exposition contained was the machine of Mr. Wicker- 
sham, of Boston, for the manufacture of cut nails. For many years 
there has been very little advancement made in the machinery for this 
manufacture. Previously to 1807, the process of nail-cutting was rude 
and slow; but about this time a machine for making cut nails was 
invented by Mr. Jesse Seed, of Massachusetts, which, both in regard to 
rapidity of production and to the quality of the product, was the source 
of an immense improvement ; and it is Seed's machine which is now in 
general use. The cost of producing nails was reduced by Seed's ma- 
chine to one-tenth of what it had previously amounted to. 

The machine of Mr. Wickersham is destined to make a revolution in 
this manufacture which may possibly prove to be no less important than 
that which followed the introduction of the earlier invention just men- 
tioned. It produces a nail which is pointed like a chisel, and being ta- 
pered through its whole length, is much better than the old one for use ; 
being more easily driven and holding more firmly in consequence of its 
breaking the fibre of the wood so little that it clings strongly and uni- 
formly the whole length of the nail. 

Heretofore, the plate from which the nails are cut has been made only 
equal in width to the length of a single nail. The machine would there- 
fore cut but one at a time. In the Wickersham machine a sheet of metal 
from twenty to twenty-five inches wide presents its edge to a series of 
cutters, which cut simultaneously a row of nails, more or fewer in num- 
ber-according to their length, from the entire edge of the sheet. It is an 



wickersham's nail machine. 249 

important feature of the machine that it economizes the metal so that 
the waste is reduced almost to nothing. The nails are cut out perfect 
and headed all at one operation. 

The amount of work which this machine will do in a given time is 
very extraordinary. 

In cutting half-inch patent brads or shoe-nails from a twenty-inch 
plate, there is a series of forty nails cut at each stroke of the knives, or 
one hundred and sixty per second, the machine driving the knives four 
times per second. Of patent brads from three-eighths to two inches long, 
and shoe-nails of all sizes, one machine will cut three thousand six hun- 
dred pounds per day. Of the larger sized nails, say of six to twelve 
penny nails, one machine will cut five thousand pounds, and of ship 
spikes one-quarter to three-quarters of a pound each, one machine will 
cut twenty-five thousand pounds per day of ten hours. 

The machine consists of an iron stand or table, from which projecting 
frames rise to hold the head-piece that carries the cutters. This head- 
piece rocks on side bearings, and from the back of it project two short 
arms, to which a connecting rod is attached by means of a pin passing 
through them, and which communicates a rocking motion to the cutter- 
holder from a crank in the driving- shaft, which gives a stroke of three 
and a quarter inches. To one end of the crank shaft is fastened a pinion, 
which gears into a cog wheel having twice its number of teeth, and which 
therefore makes but one revolution to two revolutions of the pinion. On 
this cog wheel is a double-cutting cam for giving a lateral motion to the 
iron plate from which the nails are being cut. Just above this cam, and 
held in brackets projecting from the side of the frame, is a shaft, from one 
end of which depends a small crank, the pin of which works into the cam 
above referred to ; and rising from it perpendicularly are two levers, which, 
by means of two connecting rods, communicate the lateral motion to the 
feeder. The feeder consists of a rectangular framework of iron, resting 
on two lateral guide bars moving in small studs projecting from the ta- 
ble of the machine frame. On the hinder guide bar is cut a small tooth 
wheel, and to it is attached a ratchet wheel, which is worked slowly for- 
ward by means of an arm attached to the pawl, which passes over a cam 
as the feeder receives its lateral movement. Working in grooves in the 
sides of the rectangular framework of the feeder is the feeder itself, to 
the forward part of which the iron plate from which the nails are to be 
cut is securely fixed by a small vice, and on the under side of the back 
projection of the feeder is a long rack working over the small tooth wheel 
cut in one of the lateral guide bars. 

The cutter-head has ten cutters fitted into it two and seven-sixteenths 
inches wide, that being the length of the nails being made. These cutters 
are set alternately at different levels, the first, third, fifth, seventh and 
ninth being placed about a quarter of an inch behind the others ; and 
every other cutter in each set is alternately placed at a different angle for 
the purpose of giving the proper shape to both sides of the nail ; thus, 



250 PARIS UNIVERSAL EXPOSITION. 

for instance, the first and third cutters would be employed iu making 
one nail, the first giving the proper shape to one side of it, whilst the 
third completes the nail by cutting it from the plate and giving the proper 
shape to its other side. Similarly the third and fifth cutters also act to- 
gether, the second and fourth, the fourth and sixth, and so on ; and the 
nails are so formed that they are cut alternately with their heads in op- 
posite directions, the piece that is detached for forming the head of one 
nail resulting in the formation of a pointed end to the next one to he 
cut out } so that the nails if arranged on a table in the same order as 
cut would reproduce the original plate. The cutters are so made that 
they slightly compress the nails in cutting, thus preventing raggedness 
or twisting. 

As soon as one set of nails has been cut out and the cutters are raised, 
the cam on the large tooth wheel, working through the armature and 
levers attached to the side of the machine, pushes the iron plate side- 
ways for a distance equal to the length of two nails ; and at the same 
time the small ratchet wheel on the feeder, by causing a partial revolu- 
tion of the small pinion on the guide bar, gives a slight forward move- 
ment to the plate equal to the thickness of the nail to be cut. Immedi- 
ately after another cut is completed and the cutters raised, the cam 
again comes into play and draws the plate back again to its former posi- 
tion 5 a similar forward feed again takes place, and another lot of nails 
are made. Thus it will be seen that two more cutters will always be re- 
quired than the number of nails to be made at each stroke ; and in the 
machine at the Paris Exhibition, which makes eight nails per stroke, 
ten cutters are necessarily employed. 

EVRARD AND BOXER'S HINGE-MAKING MACHINE. 

A most remarkable machine, considering the nature of the work which 
it performs, and the surprising rapidity with which it does its work, was 
exhibited in the French section by Messrs. Evrard and Boyer, of Paris, 
for making brass butt-hinges for doors. The material is placed in the 
machine in coils, there being two coils of sheet brass for the two halves 
of the hinge-body, and a coil of wire to supply the connecting bolt or 
rivet. The material is drawn off from the coils as it is wanted, the 
wings of the hinge are stamped out by punching dies to the proper 
shape, the salient parts, which are to form the tube for the connecting 
bolt, are formed upon the wire itself which is to furnish the bolt, and 
this is then cut off to the proper length. Before the hinge is dismissed, 
the screw-holes, by which it is to be secured to the wood, are formed 
and countersunk to the form of the screw-head. The machine in ope- 
ration at the Exposition threw off a complete hinge every second. A 
large variety of patterns were exhibited along with the machine: and 
the manufacturers keep a number of the machines of different sizes 
constantly in operation at their establishment. 7 Bue du Faubourg du 
Temple, Paris. The quality of the hinges compares very favorably 



DRESSING MILLSTONES BRICK MAKING. 251 

with that of similar articles manufactured by the ordinary and slower 
methods. On the whole this is one of the most remarkable examples 
of the economy of machinery which the Exposition contained. 

MACHINE FOR DRESSING MILLSTONES. 

A machine for preparing the surfaces of millstones with the regular 
teeth or notches necessary for effective grinding was exhibited by Mr. 
A. Morisseau, of Montargis, and appeared to perform its work very 
well. As the notches are to be cut in lines radiating from the centre, a 
central axis is fixed to the stone, the surface having been first made 
smooth and the large indentations having been cut in it by hand. The 
axis carries a radial arm which supports the tool to be employed in the 
dressing, and this tool is raised and dropped by a cam. After each 
blow the tool advances its own breadth along the arm, and the stroke is 
repeated. The force of the blow, or the depth of the cut, is regulated 
by an easily managed adjustment. The arm carries an apparatus for 
sharpening the tool, consisting of two rapidly rotating emery wheels, 
between which the edge maybe passed without removing the imple- 
ment from the machine. When one radial line is completed the arm 
has a slight movement of rotation, and another is commenced. The 
cuts produced by this machine have the advantage of those made by 
hand cutting, of being much more uniform and well executed. In addi- 
tion to this the process is greatly more expeditious, and therefore, where- 
ever the construction of millstones takes the character of a manufac- 
ture, it has the recommendation of superior economy. 

BRICK-MAKING MACHINES. 

The number of machines for the manufacture of brick is constantly 
increasing, and the great superiority of the product which they turn 
out, combined with the rapidity of production, is likely to secure for 
machine-made brick the command of the market to the entire exclusion 
of any other, except in situations remote from the great centres of com- 
merce or the great channels of transportation. These machines may be 
distinguished into two classes : the first including those in which the 
bricks are moulded from plastic clay, and the second those in which the 
material is employed "dry; 77 by which term, however, it is meant only 
that the material is used with such small amount of water as it natu- 
rally contains when taken from the earth. In fact, when the clay is 
literally dry, some moderate degree of moisture must be artificially 
imparted to it ; and this is accomplished, in Wilson's British process, by 
passing the material through a steam-chamber. On the other hand, 
when the season is wet, or when the natural source from which the clay 
is derived is always wet, it is necessary to diminish the amount of moist- 
ure ; an effect which is most easily secured by keeping a supply of dry 
clay under cover to mix with that which comes from the bed too highly 
charged with moisture. 



252 PARIS UNIVERSAL EXPOSITION. 

For the purpose of forming solid brick for building, the dry process 
is preferable, on account of the facility and safety with which the 
moulded masses may be handled immediately as they come from the 
moulds, without being liable to be deformed or distorted; and also 
because of the saving of the time which must be allowed, in the case 
of the wet moulded-brick, for drying. This drying process is moreover 
attended with a necessary exposure to the weather; and rains very 
often occasion serious damage when they occur during its continuance 

Gregg's brick-pressing machine. — At the Exposition of 1867 the 
machine which seemed to be most in favor was that of Mr. Isaac Gregg, of 
Philadelphia, in which the brick are formed by the dry process with great 
rapidity. This machine was doubly exhibited, being presented in model 
in the palace, and in actual operation in the neighborhood of the Champs 
de Mars, during all the period of the Exposition. The material, after 
being screened and crushed, is elevated into a hopper, from which it is 
admitted alternately on opposite sides into the moulds, where it is pow- 
erfully compressed and delivered directly to the attendants to be con- 
veyed immediately to the furnace. The brick, after burning, present a 
perfectly uniform and compact appearance. Their surfaces are smooth, 
their forms entirely regular, and their tenacity remarkable. 

David & Company's brick machine. — Messrs. David & Co., of 
Havre, exhibited another dry moulding machine, in which moulds carried 
by a rotating table receive the clay successively as the table turns; each 
mould afterward coming under the action of a piston adapted to it in 
form, which compresses the clay to the necessary degree. The bottom 
of the mould is removable, and the brick, after compression, is with- 
drawn below. The rate of delivery is as high as fifteen hundred per hour. 

The pressure exerted in moulding, it is stated, should be according 
to the nature of the earth used. When this is unctuous and damp, the 
pressure will not require to be considerable. When it is dry and inco- 
herent, the pressure will require to be greater. Thus ten kilograms 
per centimetre of surface will be a pressure proper for some earths, but 
too great or too small for others. This machine, it is stated, will produce 
bricks of from fifty -four to seventy millimetres (from two to three inches) 
in thickness. An engine of four horse-power will be sufficient to drive 
it, and the labor required to utilize its performance may be labor quite 
unskilled in the work of brick-fields. 

Durand's brick machine. — Mr. F. Durand, of Paris, exhibited still 
another dry-moulding machine. In this the earth is thrown into a 
hopper, at the bottom of which is a square piston which compresses it 
in successive charges into a mould immediately beneath by a horizontal 
motion. The bricks, as they leave the mould, are deposited on an end- 
less way, which carries them off to the place where the attendants are 
stationed to remove them. By a peculiarity of the mechanism, the 
pressure, which at first gradually increases, becomes very energetic at 
the last moment. The number of brick delivered per hour is said to be 
fifteen hundred. 



BRICK-MAKING MACHINES. 253 

Allemand's brick machine. — Still another machine operating- on the 
same principle was exhibited in the French department by Mr. Allemand. 
In this a long series of moulds are carried successively under the com- 
pressor in an endless band, the moulds themselves conveying away the 
bricks after compression. 

Hertel's PLASTic-fCLAY brick machine. — Quite a variety of ma- 
chines were exhibited in which clay in the plastic form is the material 
used. Of these a very striking one was from Menburg, in Prussia, the 
invention of Mr. Hertel. The description of this machine, as given by the 
inventor, represents it to consist of: First, " a plain flatting mill or cylinder 
for common clays, and of a double one for hard and stony ones. These 
rollers not only roll the clay, but grind and crush all the hard matters 
therein, the wiiole passing off in thin slabs or films to the horizontal plug 
mill placed beneath. Secondly, in the inside of the horizontal plug mill 
rotates a screw formed of intersecting blades of a new and special con- 
struction, which cuts and mixes the materials, at the same time conveys 
them into a compartment in which they are subjected to great pressure, 
and from thence pass through openings in the mouth piece, ready moulded 
and forming the products desired. When the machine is applied to manu- 
facturing either solid or hollow bricks, a compound homogeneous mass or 
stream sufficient to form four bricks is at once and in a continuous manner 
expressed through the plate die. This mass in travelling along is carried 
on a slide, and is separated longitudinally into four parts by steel wires 
operating by the action of the machine. Thirdly, the cutting apparatus 
on said slides, which separates crosswise in a regular right angle the four 
said parts so as to produce at once four perfect bricks, which are removed 
from the slide after each movement of the cutter. This operation is done 
while the stream of clay is continually advancing." 

They also claim that " this machine has solved an important problem, 
viz : the manufacture of bricks and other ceramic products possessing 
all the various qualities desired, by using either rich or poor clays, and 
either arable or stony;" and add that, "in fact, the calcareous bodies, 
limestone and silex, are so ground and reduced to pow r der as to neutralize 
their disadvantageous effect. The mixture of sand and cinders with any 
clay is, under the action of this machine, rendered quite homogeneous." 

Tbe rapidity of manufacture is not, however, quite so great as in the 
case of the machines above spoken of. Of solid brick, and of rectangular 
hollow brick, there are delivered from one thousand to one thousand five 
hundred per hour ; of flat tiles two thousand to three thousand ; and of 
drain pipes and mouldings, variable quantities according to size. 

These hollow bricks are formed in the same manner as lead pipe, by 
being expelled through a die with a solid core. They have a degree of 
solidity unusual with moulded bricks made from wet clay. The quantity 
of water used is in fact only so much as is necessary to insure plasticity, 
so that the clay is very stiff before compression, and the bricks come 
from the die firm and solid so as to permit their being piled up immedi- 
ately to a height of six bricks superposed edgewise. 



254 PARIS UNIVERSAL EXPOSITION 

The whole apparatus requires the attendance of three men ; one for 
introducing the raw material, another for cutting off in desired lengths 
the plastic mass or the continual stream of solid clay on its issuing from 
the plate die, the third for the removal of the bricks or objects formed. 

The motive force to be used varies from eight to twelve horse-power. 

Boulet Brothers' brick machine. — There were present at least 
seven or eight other machines for moulding bricks aud tiles from soft 
clay, all having their merits. That of Boulet Brothers, of Paris, appeared 
to be very efficient. In this the pressure is given by an eccentric, as in a 
punching-press actiug upon a die or mould. Also a machine for making 
hollow brick, in which two plungers, fed from two hoppers, force a bar of 
clay out at each end, these bars being cut in half by intervening plates of 
iron before the clay issues from the machine, so as to render the thickness 
suitable for a brick; also with proper fixed mandrels to make the bricks 
hollow, the stream of clay being formed with longitudinal channels in it 
by these mandrels. The clay riband is cut into the lengths proper for 
bricks by bringing down over it a frame with proper cutting wires. 

Schimerbor Brothers' brick machixe. — Schinerbor Brothers, of 
Mulhouse, also exhibited a machine in which the clay, after being crushed 
between rollers, somewhat in the manner of HerteFs, was expelled in a 
continuous rectangular mass, which was cut by wires into proper lengths 
for brick, very much as is done in the analogous machine just mentioned. 

CAZEXAVE & CO^IPAXV'S, SCHLICKEVSErs'S. AXT> SCHLOSSER'S BRICK 

machines. — Cazenave & Co., of Paris, exhibited two machines belong- 
ing to this class — Mr. Schlickeysen, of Berlin, one. and Mr. Schlosser, 
of Paris, one. In these two last the clay is ground and tempered by 
means of vertically revolving helicoidal compressors. 

Borie's brick 3IACHIXE. — Mr. Borie, of Paris, exhibited a machine 
for working soft clay, which was provided with contrivances for rejecting 
pebbles and other solid bodies from the mass, and which was capable of 
not only forming hollow bricks, but hollow rectangular tubes, large 
enough for Avail flues or even for chimneys of moderate size. His largest 
tubes are thirty-two inches on the longer side, and twenty-four on the 
shorter side of the rectangle. 

HOGLEX AXD CrRAFFLTX'S TOBACCO-CUTTING- 3IACHIXE. 

Messrs. Hoglen & Grafflin, of Dayton, Ohio, exhibited a machine for 
cutting tobacco, which seemed to possess the united merits of great 
rapidity of action and remarkable thoroughness of work. To this it 
may be added that the machine is easy of management, and that it 
economises material as well as time. The construction of this machine 
can hardly be made clearly intelligible without figures, but the mode of 
its operation may be concisely described as follows : 

The tobacco which has to be cut is placed in a wooden trough with its 
bottom formed of an endless web, Avhich advances it to the pyramidal 
feeding mouth, where it is caught by two endless webs of brass plates 



TOBACCO-CUTTING SHOE-MAKING. 255 

connected by pitch-chains which gripe the faggot of tobacco above and 
below, and simultaneously propel it through the narrowing mouth until 
it issues at the throat, sufficiently compacted to be readily cut by a pair 
of rapidly revolving blades. The length of the pieces into which the 
tobacco is cut is regulated by altering the rate of the feed, which is 
done by changing the system of gear-wheels by which the mass is 
advanced. 

Such a machine as the one exhibited will cut from one thousand five 
hundred to six thousand pounds of tobacco per day, according as the 
shredding is finer or coarser. When the tobacco reaches the knife, it is 
compressed into a hard mass of one-fourth the original bulk at the feed- 
ing mouth. A wooden drum is attached to the part at which the knives 
revolve, where the shred tobacco is collected and withdrawn through a 
drawer. As the feed is continuous, there is less loss by butts than when 
it is intermittent, and less loss by shorts in dressing. The rapid action 
also obviates any darkening of the color by heating, and the compressed 
mass can be run backward when the knives are being adjusted, which 
saves loss by swell. The machine is rapid in its action, and is in all 
respects highly efficient. The weight of the machine is three thousand 
pounds, and it requires a motor of four horse-power to drive it. The 
discharge mouth measures four inches by ten ; the knife makes from 
eight hundred and fifty to one thousand revolutions per minute. 

SHOE-MAKING MACHINES. 

Shoes fastened by pegs or nails have long been manufactured on a 
large scale in the United States; but in general, if not universally, the 
work has been done by hand. Since the year 1844, screws have been 
employed more or less extensively in France for the same purpose 5 and 
machines have been gradually introduced to replace manual labor in 
different parts of the process of manufacture, until at length, in many 
large establishments, hand- work is dispensed with altogether. The 
French department of the Exposition presented a number of very inter- 
esting examples of shoe-making machinery; and one house, that of 
Dupuis & Co., of Paris, illustrated the whole process of manufacture from 
the beginning to the end. Machines for securing the soles by means of 
screws were also exhibited by Messrs. Lemercier, Brice, Cabourg, and 
others, differing in some of the details of their construction, but all per- 
forming their work with admirable rapidity. 

The machines exhibited by Dupuis & Co. formed a complete series, 
by the successive operation of which a pair of shoes could be produced 
from the raw material in from one to two hours. The leather is cut into 
shape by means of tools resembling punches. The thicknesses which 
are to form the soles are united with glue and compressed previously to 
being cut. They receive then the necessary concavity by powerful 
hydraulic pressure; and their surfaces are smoothed and hardened in 
still another machine. Sewing machines form all the necessary seams, 



256 PARIS UNIVERSAL EXPOSITION. 

binding, and, if necessary, ornamental stitching of the upper leathers ; 
and then the separate parts are brought together in the important 
machine which is to complete the shoe by uniting the upper leather and 
the sole. 

First, there is placed upon the form or last in this machine the inner 
sole. The upper leather is then stretched over this by means of small 
nippers attached to the machine, which are capable of stretching it with 
considerable force. It is secured in place by a row of small nails. The 
outer sole is then carefully applied over the whole. As this has been 
entirely finished and polished on the edges in the previous process of 
preparation, it is important that it be truly adjusted, since it cannot be 
afterwards trimmed. The machine then applies to the two soles, with 
the upper leather included between them, a force of pressure of not less 
than three hundred kilograms, increased, if desired, to one thousand 
kilograms, or one ton. Screws are then inserted all round the margin 
of the sole, an operation completed in the most rapid machines in less 
than three minutes for a single shoe, or in five minutes for a pair. The 
salient extremities of the screws are cut by a chisel, and the burr left by 
the chisel is ground away on an emery wheel. The last on which the 
shoe is constructed being made of iron, prevents the interior extremities 
from passing the surface of the inner sole. 

The machine is provided with an indicator, by means of which the 
exact distance desired between the screws may be easily preserved. 
For different sizes and kinds of shoe this distance will vary, as well as 
the size of the screw itself. Any kind of shoe may be made in the 
machine, from the coarsest boots to the thinest dancing pumps. 

An important feature in these machines is, that they not only apply, 
but make the screw. The material is brass, which is drawn off from a 
bobbin in the machine as it is required. The extremity passes horizon- 
tally through a guide, and, in order to cut the thread of the screw, the 
whole bobbin revolves. In hand machines a crank serves to give the 
revolution ; but the driving power may be taken from a motor. When 
the resistance shows that the screw has struck the iron last, a cutter is 
brought into action by the foot of the operator pressing upon a pedal, 
and the wire is cut as near as possible to the leather. 

Screw-fastened shoes are becoming more and more generally used in 
France. They cannot fail soon to replace pegged shoes everywhere, 
since the fastenings are much stronger and more durable, while the 
rapidity of the manufacture must greatly surpass that which is attain- 
able in the use of wooden pegs. Whether they will equally supersede 
sewed shoes remains to be seen. 

CORSET-WEAVING- ZtfACHINE. 

The Convex Weaving Company of Xew York exhibited a very inge- 
nious invention in the form of a machine for weaving corsets for ladies. 
Though the design of the invention was thus special, and though it is 



CORSET- WEAVING MACHINE. 257 

thus far, it is believed, confined to weaving- the articles above named, it 
is, nevertheless, capable of being applied to every variety of fabric 
which it is necessary to adapt to a figure of undulating contour or vary- 
ing dimensions. Thus a waist for an external garment or a coat for a 
man might be woven on this principle with similar facility. It may be 
a question whether dresses could be made as elegant in this way as from 
stuffs woven in the ordinary loom and afterwards cut and fitted ; but 
there is no doubt that they could be made entire in any form without 
seams. The corsets are not only made complete in form, but they are 
also furnished with the tubular spaces or channels required for the intro- 
duction of whalebones. The machine is capable of making forty pairs 
of corsets in ten hours. The following is the inventor's description : 

a The principle of a constant length of travel for the shuttle was 
adopted for the sake of simplicity; but as it is necessary, in weaving the 
gores, that the weft thread should pass through only a part of the 
breadth of the warp, the Jacquard has been employed for the purpose 
of taking up the portion of the warp required to be woven in that part. 
As the shuttle always passes over the full breadth of the warp, of which 
only one portion, say one-third, is to be used, it unwinds the full length 
of weft thread from the bobbin, but only one-third of it is tied in the 
warp. In repassing the shuttle one-third more is tied, thus leaving one - 
third of the unemployed weft thread in the form of a loop upon the 
article manufactured. 

" To remove this superfluous thread, the thread-catcher, which is a 
lever with an elastic finger, passes from behind, through the lay on each 
side of the reed, and pulls the thread out. 

" In consequence of this partial opening of the warp the fly-shuttle 
could not be used, and another contrivance had to be resorted to. This 
consists in a carrier by which the shuttle is conveyed to the centre of 
the warp, where it is taken by the other carrier and passed through the 
warp. By these carriers a very even motion, free from all sudden jerks,, 
is imparted to the shuttle, so that the finest silk and the loosest wool 
can be worked with this lay as neatly and easily as by hand, without 
the least danger of breaking the thread, as would happen with the fly- 
shuttle. 

" The most difficult part of the work is performed by the regulator or 
take-up motion, the action of which is to take up the woven cloth in such 
a manner as to leave a straight line in front of the reed. As the cloth 
is woven first only on one side ; then, for the whalebone pockets, where 
the cloth is double, evenly over the full breadth ; thirdly, on the other 
side only ; and, finally, for the full breadth at the back and front of the 
stay, the motion of the regulator must change accordingly. To effect 
this the cloth passes between two sets of rollers, the upper of which are 
simple pressure rollers, to be regulated by springs and set screws. The 
lower rollers are fluted and worked by a system of levers independent 
of each other. The levers are Avorked conjointly by the Jacquard and 
17 i A 



258 PARIS UNIVERSAL EXPOSITION. 

lay, so that the lav gives only a movement to those levers which have 
been previously acted upon by the Jacqnard. 

"A very elastic warp tension is obtained by a peculiarly constructed 
lever combined with an elastic brake, so as to render the whole machine 
fit for any kind of work — flat or convex, plain or richly ornamented — 
according to the cards placed upon the Jacquard, and the material put 
in warp and shuttle." 

CHENILLE-MAKING- MACHINE. 

A small machine, apparently simple in its construction, but never- 
theless qnite puzzling to the spectator of its operations, was exhibited 
by F. Martin, of Lyons, for the manufacture of chenilles. In this man- 
ufacture, by whatever process conducted, the material is continually 
reflexed upon itself, so that the article in the first instance presents a 
series of close loops which must be cat to give it finish. The machine 
of Mr. Martin performs the operation of weaving and cutting at the same 
time ; and the finished chenille is turned out with a rapidity which is 
truly marvellous. The particular machine in operation at the Exposi- 
tion produced more than two and a half yards a minute, and the quality 
of the product is much superior to that which was furnished by pro- 
cesses previously in use. The invention of this machine is not very 
recent, as it dates back to 1851, but it has given a large development to 
the manufacture. Mr. Martin, in a note to the committee, has furnished 
some interesting information on this subject. He states the production 
of chenille, in France alone, to amount at present to five or six millions of 
francs annually. The manufacture is also carried on in England on a 
very large scale. There are now in that country some thousands of 
machines in operation. One manufacturing establishment at Derby, 
near London, in operation ten years, has declared dividends to the extent 
of 750,000 francs. Mr. Martin adds : " I have taken no pains to make this 
machiue known; it has made its own way from the beginning; I did not 
trouble myself to patent it, though I have patented more than twenty 
other inventions. Other mechanicians have constructed machines to 
accomplish the same end. Most of these machines are designed to 
manufacture two pieces of chenille at once : some of them more. Ac- 
cording to the excellence of the mechanism and the capacity of the 
workman, these machines will produce on an average a thousand to 
fifteen hundred metres of chenille a day. There are workmen of excep- 
tional ability who will make more, but rarely. For the sake of ascer- 
taining the productive power of a machine, I have myself pushed the 
production up to twenty-five hundred metres; but this rate could not be 
permanently maintained. All my machines have been made for a single 
piece, for which the management is easiest and most agreeable. The one 
at the Exposition, under the direction of an intelligent workman, makes 
on an average fifteen hundred metres a day. This form of the machine 
is adapted to all sizes of chenilles, which is not the case with most others. 



CHENILLE MAKING — PAPER FOLDING. 259 

"Chenilles are now employed in a great variety of novelties — shawl 
fringes, embroideries, head-dresses, tissues, &c., &c. The new manufac- 
ture has entirely subverted the old, which was carried on by weaving. 
The product was by no means so beautiful, and the sale was compar- 
atively trivial, not having exceeded two or three hundred thousand 
francs for France ; and I am not aware that the manufacture had any 
existence elsewhere. It required a much larger capital, which was itself 
a serious obstacle in the way of production.' 7 

At a comparatively late period of the Exposition there appeared a 
rival and more recently invented machine for the same manufacture, 
for which patents have been taken in France, England, and our own 
country. This was a machine making several pieces at once, producing, 
as was stated, an "enormous" daily fabrication, though the amount was 
not given in numbers. But the special merit claimed for it by its inventor, 
Mr. L. Couchoud de Gournay, of Paris, was that it requires so little 
superintendence as to make it possible for twenty-five or thirty machines 
to be managed by a single woman; whereas the ordinary machines exact 
the exclusive attention of a skilled workman for each. 

Both these machines are exceedingly ingenious, and happily illustrate 
the extent to which a single and apparently minor invention may develop 
an insignificant industry into an important branch of manufacture. 

PAPER-FOLDING MACHINE. 

A machine for folding printed sheets has been in use in some of the 
newspaper offices of our country, and perhaps continues still to be used ; 
but no such machine, so far as the knowledge of the writer extends, has 
been here found available for folding book sheets, or has performed its 
task with a sufficiently accurate register for that purpose. In general, 
also, the number of folds given to the sheet has not been sufficient to 
serve for book forms. 

In the French section of the Exposition there was constantly to be seen 
in operation throughout the season a very compact and efficient folding 
machine invented by Messrs. Fredereau and H. de Ohavannes, of Paris, 
in which sheets requiring many folds were very rapidly and very accu- 
rately reduced to book form. The machine received the sheets from an 
attendant, whose duty it was to adjust them at starting to two deter- 
minate marks of reference, after which they were whirled through the 
machine with surprising rapidity, and turned out almost immediately 
neatly folded, and with an exactness of register rarely seen in the best 
hand work. As books usually require to be divided at least once, this 
machine is constructed so as to make the necessary cut, and to fold the 
two halves independently. A little statement of the history, the prin- 
ciples of construction, and the economical usefulness of the machine, 
printed in 32mo., and folded by the machine itself, was distributed to 
visitors. The inventors say in this that they were induced to undertake 
the construction in consequence of the steadily increasing cost of hand 



260 PARIS UNIVERSAL EXPOSITION. 

work, and the difficulty of finding persons willing to submit to a labor so 
fatiguing and so ill-paid. There were also great inconveniences to pub- 
lishers arising from the necessity of letting this work go out of their 
establishments to be performed by operatives in their own homes ; in 
consequence of which they were liable to loss, injury, and delays, and 
were able after all, in many instances, to secure only a very ill-executed 
description of work. The inventors profess to have acquainted them- 
selves with the forms of folding machines heretofore introduced into 
America, England, Switzerland and France, but say that none of these 
have been equal to any but the simplest kind of work, and none of them 
have been sufficiently rapid to be truly economical. In their own 
machine they say that the mode of presenting the sheet, the saws which 
divide it, and the arrangements which allow the parts to be adjusted to 
sheets of different sizes, are all original. 

The rapidity with which the machine can be made to work depends 
upon the aptitude and dexterity of the operative who presents the sheets. 
An attendant of ordinary skill has been experimentally found capable 
of adjusting and presenting from one thousand to twelve hundred sheets 
per hour 5 which, completely folded in 32mo., are an equivalent to the 
work of ten or twelve practiced folders by hand. This is evidently a 
considerable economy, since the force required to drive the machine is 
insignificant. Moreover the experiments on which these figures are 
based were made in the earlier period of the history of the invention, 
and more recent improvements have considerably facilitated the work 
of presenting the sheets, so that the economy is really greater than it 
seems. 

On the other hand, when the number of folds required is smaller, the 
economy is less, since the number of sheets presented will still remain 
the same, while hand laborers despatch more in proportion as the required 
number of folds diminishes. Hence, therefore, for a quarto form the 
machine will do only about the work of two workmen ; and for a folio, 
only the work of one. For a single fold, therefore, there would be really 
no economy, but, per contra, no one would think of using a machine to 
make but a single fold. 

The inventors suggest, however, that even for a single fold an advan- 
tage would be found in placing the machine in immediate connection 
with the printing press, and causing the sheets to be automatically pre- 
sented. This for newspapers would be very feasible, but not so for 
books, in which case the sheets require to be dried and pressed before 
being folded. 

Apparently this machine is destined to be better known. Admirably, 
however, as it certainly performs its work, it is not in all respects so 
complete as one or two which were exhibited in London in 1862. Both 
of these were from Switzerland, and one of them, the result of the suc- 
cessive labors of two or three inventors, Messrs. Sulzberg. Graf, and 
Tanner, not only folded the sheets but stitched them. The operation ot 



PAPER FOLDING ENVELOPE FOLDING. 261 

this machine is thus described by the jury of the class in that Exposition : 
" The sheets are put singly by a boy under the points of the machine in 
the same manner as in the printing machine. A knife moving up and 
down takes hold of the sheet lengthwise in the centre, draws it through 
a slit in the table and the first fold is made. The knife returns instantly 
and the sheet is taken by a second vertical knife, folding it at right 
angles to the first fold. Before the third fold is made the stitching 
operation commences; two needles, provided with hooks, passing 
through the middle of the sheet about an inch distant from each other, 
draw through the cotton unwound from a bobbin and cut to the required 
length. The sheet is then folded a third time by a knife acting at right 
angles with the second one, which takes hold of the sheet and pushes it 
between a pair of ribbed rollers, whence it passes directly to another pair 
of polished rollers, and remains glazed on the table. The machine works 
so correctly and truly that the sheets are folded and stitched with the 
utmost exactitude in the centre, and are so well pressed that the binder 
can immediately begin wrappering. It is, moreover, so constructed as to 
fold the largest as well as the smallest sheets ; and both the stitching 
and the pressing apparatus, or each singly, may be detached by the 
loosening of a screw. It can be worked by either hand or steam, a boy 
being sufficient for that purpose." 

In regard to the other machine of the London Exposition, the jury 
say: "It feeds itself without any human aid whatsoever, by means of a 
very ingenious air or sucking apparatus, which takes the sheets one by 
one from a pile under the horizontal folding knife, thus enabling it to 
fold 3,000 sheets per hour with the same precision as the first machine ; 
without, however, making so perfect a register, as no points are used in 
laying on, and it is therefore best adapted to the folding of newspapers 
or other periodicals, where a perfect register is not absolutely required." 

From these statements it appears that the Swiss machines possess 
merits not inferior to those of the French machines exhibited, while in 
this latter no provision is made for stitching the folded sheets. The 
ingenious expedient of picking up single sheets from a pile by an aspi- 
ring apparatus is becoming general in this class of industries. It is 
employed in a machine exposed in the French section designed for fold- 
ing envelopes ; and it is also used in the note-stamping machine con- 
structed for the Bank of France, elsewhere noted in this report. 

ENVELOPE-FOLDING MACHINES. 

The immense increase in epistolary correspondence which has taken 
place since the commencement of the era of cheap postage, has led to a 
corresponding increase in the consumption of letter envelopes. The de- 
mand has been so great as to make the employment of machinery in the 
manufacture a necessity. Many envelope-folding machines have accord- 
ingly been introduced, and these were numerously represented at the 
Exposition. With these machines, in their ordinary forms, the public is 



262 PARIS UNIVERSAL EXPOSITION. 

already familiar. Only one of those exhibited seems to possess sufficient 
originality or novelty to require mention here. This is said to be a Brit- 
ish invention, although it was not exhibited in the British section. The 
exhibitors were Messrs. Bobineau and Bouinestant, of Paris. 

The peculiarity of this machine is a very ingenious application of the 
principles of pneumatics to effect certain parts of the operation, with 
the advantage of a material simplification of the mechanism, and a very 
important increase in the rapidity of working. The pneumatic appa- 
ratus acts, in different stages of the process, both by aspiration and by 
insufflation. Aspiration or exhaustion is used to lift and transport the 
paper to the place in the machine where it is to be folded, and insuffla- 
tion, or a blast produced by compression, subseqently bends over the 
four angles into a position to receive the pressure of the platen which 
folds them. 

It is, of course, understood that the paper has been already cut to 
proper form before being introduced into the folding machine. This 
process of cutting is machine work also ; and it presents the sheets in 
piles like solid blocks, all having the form of an envelope opened out 
flat. One of these piles or blocks is placed upon a plate or tablet in the 
machine, to which a periodical motion of elevation and depression is 
given by means of a cam and spiral springs. At each upward move- 
ment the pile meets the aspirator, which is a forked tube, the two 
branches of the fork being flattened, and perforated on the under side 
with numerous minute holes. The tube which forms the handle of the 
fork communicates by means of an India-rubber tube with the air-pump. 
As the pile of sheets comes in contact with the perforated tubes, the 
upper sheet adheres to them by the effect of the aspiration, or sucking, 
and when the pile falls away this upper sheet remains suspended. In 
consequence of the bifurcation, it is held by the parts which are subse- 
quently to be folded over. The aspirating tubes are sustained by a 
carriage which now runs forward and transports the sheet to the point 
where the folding is to be performed. 

The folding apparatus consists of an open box of metal having the 
size to which the emrelope is to be reduced. Immediately over it is a 
plunger or platen of the same form as the box. So soon as the sheet is 
in place — and it is dropped more exactly in place than a workman could 
arrange it by hand without occupying a very sensible time — the plunger 
descends, and the sheet is pressed down into the metal box, so as to 
form as it were a lining to it, or a paper box of the same form : with, 
however, its four angular points standing upright. In the mean time, 
however, one or two important operations have taken place. The 
point which is to form the lower side of the envelope, and to fold over 
the two ends, is gummed, and the opposite point receives any stamp 
which it may be desired that the completed envelope shall bear in the 
place of the seal. The exhaustion in the aspirator then gives place to 
insufflation, the paper is released, the platen descends, the aspirator 



ENVELOPE MAKING FRICTION MATCHES, 263 

withdraws to pick up another sheet, and the platen rises again, leaving 
the paper lining the metal box as above described. 

In the sides and ends of the box, near the bottom, or just above the 
fold in the paper already made, there are perforations in a horizontal 
line, through which, in the present state of things, there enters a strong- 
blast of air, which has the effect to bend all the upright sides of the 
paper lining inward so far that a second descent of the platen occurring 
at the same time completes the folding and fastening of the envelope by 
a single movement. The platen rises once more, the bottom of the box 
drops, and the envelope is thrown out. 

It is of course necessary that the angles of the paper, when bent in- 
ward, should observe a certain order. The ends must bend first, the 
lower angle next, and the upper angle last. This invariable result is 
secured by the very simple expedient of admitting the blast to the sev- 
eral sides in this same order. The difference in the actual time of ad- 
mission is indeed very small ; but the smallest difference suffices for the 
effect. 

A single machine of this description will fold twenty thousand envel- 
opes in a day of ten hours, or about two thousand an hour. This great 
expedition is chiefly owing to the extreme facility with which the sheets 
are picked up separately by the aspirator, and the exactness with which 
they are put down in place, without any loss of time. No other me- 
chanical means could be relied on to perform the first part of this work, 
and to do it by hands is both troublesome and slow. This same princi- 
ple (aspiration) has been found advantageous in other machines for 
working in paper; as in the Swiss book-folding machine just mentioned ; 
and its evident capabilities are such that we may expect to see it here- 
after exemplified in various new forms. 

FRICTION MATCHES. 

These objects are now manufactured by machinery on a very large 
scale, with the advantage that the machine-made matches are neater 
and more uniform in appearance and better in quality than those made 
by hand. Matches of cylindrical form have been chiefly heretofore hand- 
made, and the figure has been given by compression or by drawing the 
wood through holes in a plate in the manner of wire drawing. But this, 
while improving the appearance, diminishes the inflammability and ren- 
ders the match more liable to fail. The hand-made cylindrical matches 
have been chiefly produced in Austria, from which country there has 
been a considerable exportation. A machine was exhibited by Messrs. 
Eimailho Brothers, of Paris, for manufacturing the wooden cylinders 
without compression. Many of the Austrian matches have been made 
without compression also, but still the cylinders are prepared by hand. 
They are cut from large planks of fine even-grained wood, by means of 
a large joiners' plane, carrying a series of steel tubes with sharp edges, 
instead of the usual planing tool. The effect of this operation is the pro- 



264 PARIS UNIVERSAL EXPOSITION. 

ductioD of a series of long, thin splints of wood of perfectly circular sec- 
tion, which are afterwards cut up into short lengths as required. It has 
been long wished to substitute machinery for the joiners' plane in this 
operation, but the difficulties arising from irregularities of the timber 
and from other causes were very great. Messrs. Eimailho have at last 
successfully solved the problem in a very simple manner. They cut the 
blocks of wood to the exact lengths of the matches first of all, and pro- 
duce the round splints from these short blocks. By these means they 
are less dependent upon the quality of the wood, as the cut is not mate- 
rially influenced in the short length of two or three inches. The machine 
for doing this consists of a slide carrying a series of tubes made out of 
a solid piece of steel and kept sharp at their edges, and of a simple frame 
for holding the wood block in contact with the tool. The slide is moved 
forward and backward by an eccentric very rapidly, and cuts a row of 
matches at each stroke, each fresh row throwing those previously made 
out of the machine. The machine exhibited is double, consisting of two 
such slides fixed at opposite sides of the eccentric, which ^rorks both. 
The action is very rapid, the machine throwing out a small bundle of 
matches at each stroke, and the quality of the article produced is superior 
to that made by hand. Messrs. Eimailho have several such machines at 
work in their own factory. 

Machines were also exhibited for performing the operation of dipping 
the matches, by means of which the work is accomplished with wonderful 
rapidity. One of these, the invention of Mr. G. Schmidt, of Paris, would 
arrange for dipping no less than six thousand matches in four minutes. 
The splints properly cut and prepared are received upon a horizontal 
plate or table grooved to the size of the matches, and are made to 
fall into the grooves by the action of a broad brush which is suspended 
above the table, and which the operator moves by means of a pedal. 
The effect reminds one of the arrangement of coin by similar means in 
the counting machines of the mint. In front of the table on which the 
matches thus arranged lie, is a frame placed vertically, which is designed 
to receive a number of layers of matches one above another. This frame 
presents immediately before the row of matches a narrow receiving plate 
or bed. By the action of a second pedal the workman causes a row of 
needles to advance, which push forward the matches on to this plate, 
and are retracted by a spring. The matches are pushed beyond the edge 
of the receiving plate just so far as may suffice for dipping, and their 
ends are kept separate by thin partitions, which are a fixed part of the 
machine. The frame, which has a movement up and down in guides, is 
then depressed sufficiently to permit another receiving plate to be laid 
on the last row of matches, at a proper level to receive an additional 
row ; and this process goes on until sixty rows, each containing one 
hundred matches, have been piled up in the frame. The frame is then 
locked up by bringing down a traverse bar at the top. so as to compress 
the whole mass and secure it in place. The matches are thus confined 



MATCH-BOX MAKING— SUGAR CUTTING. 265 

very inuch in the same manner as the type in a printer's chase. They 
are then evened at their ends like type, and are ready for dipping. 

A machine for preparing wax-coated matches for dipping, invented 
and exhibited by Mr. Mujica, of St. Sebastian, Spain, was in some respects 
similar to the one just described. In this, however, the lengths are cut 
by the machine which arranges them, all the matches of each layer being 
cut simultaneously by one action of the knife. The material, which is 
flexible, being a cotton wick covered with wax, is placed in the machine 
in coils. From these coils, or bobbins, seventy-two little waxen cylinders 
are carried forward by the rotation of a pair of feeding rollers, and at 
the proper moment the knife cuts them, and the matches thus cat off 
rest upon a receiving plate covered with flannel. For the rest, the 
operation is essentially the same as that described above. The frame is 
depressed in this case by means of a screw, and a second plate is placed 
on the row of matches which has just been deposited. The frame will 
hold four thousand or more matches, which are secured and dipped as 
above described. The whole operation occupies from five to eight min- 
utes. A single workman will be able to prepare and finish with this 
machine as many as four hundred thousand matches in a single day. 

MATCH-BOX-MAKING MACHINE. 

The immense number of friction matches annually made and sold ren- 
ders it necessary to employ rapid modes of manufacturing the boxes 
required to contain them. An ingenious machine designed for this pur- 
pose was exhibited by Mr. L. Poirier, of Paris. The boxes are made of 
pasteboard, which is cut into pieces each of suitable size to make the 
body or the top of a box. These pieces are rectangular in form, but are 
rounded at the angles. They are introduced by hand one by one into 
the machine, and are instantly forced by a plunger into a box-shaped 
matrix, or socket, where they receive at one movement the form desired. 
In this operation the corners, in which the material is in excess, are 
folded over on the sides, and an energetic pressure is exerted on the 
folds by means of four cams; in consequence of which these folds become 
compacted into one mass with the sides of the box. The union is per- 
haps not as perfect as it might be made by the application of a little 
paste to the angle before compression, but it is apparently quite firm, and 
answers certainly perfectly well the simple purpose intended. Nearly 
three thousand boxes are manufactured per hour by one of these machines. 
The number might perhaps be increased by the addition of a contrivance 
for placing the cards in the machine without exacting the constant atten- 
tion of a workman. 

SUGAR-CUTTING MACHINE. 

A simple machine for cutting up white sugar into little cubes for use 
was exhibited in the Belgian section by Mr. W. Devisseber. The sugar 
is first prepared for the machine by means of circular saws, which reduce 



266 PARIS UNIVERSAL EXPOSITION. 

it to the form of long, square sticks. These are dropped into upright 
grooves in the machine, of which there are a number side by side, and 
of which the bottoms are movable. These movable bottoms are formed 
of a pair of plates of metal which meet in the middle beneath the grooves, 
arid when closed arrest the descent of the sugar. A little above these 
plates, at a height suitable for making the cut, are placed a pair of knife 
edges which move inward toward each other and divide all the columns 
of sugar simultaneously. As the knife edges close, the supporting plates 
open, and allow the pieces which have been cut off to drop. This recip- 
rocating action takes place rapidly, and all that is necessary to keep up 
the process is to supply the columns of sugar from above. 

BOTTLE-WASHING MACHINE. 

A machine for expeditiously washing bottles was exhibited by Mr. TV. 
E. Hickling, of Grantham, England, which seems to deserve the atten- 
tion of persons in the wine trade and of bottlers generally. Machines of 
this description are extensively used in the principal British bottling 
houses. The design of the machine is to give a rapid agitation to a large 
number of bottles at once. The immediate cleansing is accomplished in 
the same manner as in hand washing, that is, by the introduction of solid 
substances along with water into the interior of the bottles. The machine 
therefore performs very thoroughly, and upon several bottles at a time, 
an operation which is performed less perfectly and in longer time by hand 
upon a single one. The solid substance introduced is shot, with which 
the bottles are about one-third filled. They are placed in the machine 
in a horizontal position between base plates coated with India-rubber, 
and India-rubber stoppers. Eight bottles are arranged in a circle around 
a horizontal spindle, and eight more form a second group upon the same 
spindle. A rapid reciprocating motion is then given to this spindle by 
machinery, and in the meantime the spindle turns upon its axis, so as to 
bring every part of each bottle successively into the lowest position. Six- 
teen bottles are thus washed at once, and one machine driven by steam 
will wash from forty to forty-five gross of bottles per day. The bottles 
are placed in the machine and removed very expeditiously. Different 
sizes of the machine are constructed for different kinds of work. They 
are adapted to the washing of vials on the one hand not larger than of 
two ounce capacity, and. for cleansing jars, casks and barrels on the other 
of any magnitude. 

3IACHINE FOR, CORKING BOTTLES. 

To introduce a cork into a bottle mouth considerably less in diameter 
than itself, is, by the methods ordinarily practiced, a troublesome opera- 
tion, but it is one which must be performed if it is desired effectually to 
prevent the escape of the gases of effervescent liquids. A machine for 
expeditiously accomplishing this object was exhibited by Mr, Chalopin, 



ELECTRICAL DETECTORS. 267 

of Paris. In whatever mode the work is done it is necessary, of course , 
that the cork should be in the first place thoroughly soaked in hot water. 
It becomes then so soft as to be easily compressed into any shape, and in 
changing- its figure it is not in danger of being broken. 

Mr. Chalopin's machine presents at the top a funnel-shaped socket, 
opening through a metallic cross-bar. The orifice of the funnel at the 
bottom is just equal to or something less than the size of the bottle 
mouth. The bottle is placed beneath, presenting its mouth opposite this 
orifice, and a pedal, or sliding wedge beneath the bottom of it, holds it 
firmly in place. The softened cork is dropped into the funnel above, and 
a piston worked by a lever descending upon it drives it by one or two 
efforts completely into the bottle, when it may be secured in the usual 
way. It is unimportant to the success of the operation which end of the 
cork goes first. The sloping sides of the conical funnel reduce its 
diameter with the utmost facility, and the whole operation is complete 
in two or three seconds. 

II. MISCELLANEOUS INVENTIONS. 

ELECTRICAL DETECTORS, APPLIED TO POWER LOOMS. 

One of the most useful additions which has been made within the past 
few years to the machinery for weaving, has been a system of electrical 
detectors designed to give instant notice whenever a thread breaks, 
either in the warp or the woof, whenever a serious defect occurs in the 
fabric, or when any part of the machinery itself becomes deranged. On 
the occurrence of any of these accidents, the motion of the loom is instan- 
taneously arrested, and the attention of the superintendent is called by 
the sound of a bell. The following notice of these ingenious contri- 
vances is derived from the London Engineering : 

" Applications of this nature, contrived by the joint invention of M. 
Eadiguet, a mechanical engineer, and M. Lecene, manufacturer of textile 
fabrics, are exhibited in the Paris Exhibition, applied to knitting-looms ; 
and to show that the principle is applicable to machines already in 
existence, they have been attached in the present instance to an ordinary 
loom not made expressly for tlie purpose. It is now some twenty years 
past since the manufacturers of textile fabrics have seen the necessity 
for some means of preventing the serious accidents which are at any 
moment liable to occur by the breaking of threads, &c, especially in the 
manufacture of the finer articles, and this the present arrangement effectu- 
ally succeeds in doing by immediately stopping the machine on the occur- 
rence of the most trifling accident. This is accomplished by so arranging 
the machine that, on the breaking of a single thread, the emptying of a 
bobbin, the accidental bending of a needle, or on holes being caused in 
the work by the knotting or thinning out of a thread, an electric circuit 
is completed, which, passing through an electro-magnet, causes it to attract 
an armature, and so releases a lever, which, actuated by a strong spring, 



268 PARIS UNIVERSAL EXPOSITION. 

withdraws a clutch through which motiou is communicated to the loom, 
and the machine is instantly stopped. It will thus be seen that, even in 
the manufacture of the most delicate textiles, one person would be 
enabled to superintend several looms. The following explanations will 
render the mode in which this may be accomplished perfectly intelligi- 
ble, and as the principle may equally well be applied to any sort of 
machine, we have not thought it necessary to further illustrate by a 
wood-cut its mode of application to any one machine. 

" One pole of an electric battery is connected with the frame work of 
the loom, while the opposite pole is in communication with all the various 
working parts of the machine which are in close contact with the tex- 
tiles, and which are all carefully insulated from the frame of the machine 
by ivory, horn, caoutchouc, or other non-conducting material ; and in 
some instances insulation between the two parts is maintained solely by 
the threads of the manufacture. An electro-magnet is connected with the 
frame of the machine, and its armature, when not attracted, supports 
one end of a lever ; on the other end of this lever is a hook by which 
another lever connected with the clutch on the driving-shaft is held back, 
and so long as it remains in this position the machine is kept in motion. 
As soon as anything goes wrong with the machine or with the work, a 
circuit is made, the armature supporting the holding-back lever is with- 
drawn by its being attracted by the electro-magnet, the spring behind 
the clutch lever causes the clutch to be withdrawn, and the loom is 
stopped. 

u It has been stated that one pole of the battery is connected with all 
the pieces of the machine immediately connected with the threads or the 
manufactured texture, and that these pieces are insulated from the body 
of the loom ; some of these pieces are withheld from connection with 
the other pole by the threads passing from the bobbins to the needles, 
and are called l break-threads, 1 for so soon as a single thread breaks, or 
a bobbin becomes exhausted, they fall by their own weight upon a bar 
in electric connection with the opposite pole, and so complete the circuit 
and stop the machine. Small metallic disks rolling on the material as it 
is made, and pressing it against the side of the machine frame, from 
which they are only insulated by the threads of the manufactured mate- 
rial, instantly detect any flaw caused by defects in the thread, which 
admit of their coming in contact Avith the machine frame itself, when 
the machine is, of course, instantly stopped. Again, plates are put 
under the needles themselves, at such a distance that, in the event of 
one of them becoming broken or bent to such an extent as to affect the 
work, it would be brought into contact with it on passing, and stop the 
machine." 

This notice overlooks what, to the visitor, appeared to be the most 
curious part of the contrivance, and which had very much the seeming 
of a veritable intelligence. This was the attachment employed to detect 
the failure or rupture of the yarn in the shuttle. The contrivance here 



ELECTRICAL DETECTORS. 269 

referred to consists of a delicate lever at the side of the loom, between 
the web and the apparatus for throwing the shuttle, which descends the 
moment the shuttle reaches the end of its course, with a motion like that 
of a finger feeling for some object of interest. If the yarn is unbroken, it 
bridges of course the space between the web and the shuttle, and arrests 
the finger, which, thereupon, as if contented, retires ; but if there is no 
yarn, or if the yarn, being broken, is slack, the finger descends further, 
and the consequence is an electric contact, which causes an instanta- 
neous disconnection of the motor, and a violent ringing of the bell, while 
the loom is stopped before time enough has passed to allow the shuttle 
to be thrown again. The movement of this little sensitive finger was 
watched with amused interest by crowds every day. It furnished one 
of the most striking illustrations of the extent to w T hich force has been 
subdued to be the submissive slave of man, putting forth and withdraw- 
ing its energies in obedience to the lightest touch ; and that touch not 
even applied by the living man himself, but by a delicate and uncon- 
scious apparatus to which he seems to have transferred a part of his own 
consciousness. 

In connection with the alarm bell, it is proposed by the inventors to 
add a visible indicator which shall point out to the attendant the partic- 
ular place where the rupture or derangement has occurred. This, it will 
be obvious, will be a material advantage in respect to economy of time ; 
for when there are so many little sentinels on the watch, it will not be easy 
at once to discover, without such assistance, which it is which has given 
the alarm. 

The following relates to the application of similar detectors to stock- 
ing-looms, or more generally to machines for knitting of every descrip- 
tion, many of these being employed in the manufacture of under-gar- 
ments for the body, of knitted scarfs, shawls, &c. Several machines of 
this class were exhibited by Messrs. Berthelot & Co., of Troyes, among 
which both the circular and the rectilinear forms were represented. It 
was claimed for these as a main point of superiority, " that by the substi- 
tution of a segment of a large circle for the small wheel which governs 
the action of the needles, the thread is exposed to a less rapid change of 
direction, in consequence of which it is less liable to fracture, especially 
in the case of fine yarns. One of the circular looms on exhibition was 
weaving No. 34 yarn, and the fabric produced was of remarkable fine- 
ness and flexibility. In two of the circular loom of these makers, 
arrangements are introduced whereby the breaking of a thread will at 
once notify the fact to the attendant, in the one case by ringing an 
electrical bell, in the other by stopping the machine. 

"In the electrical arrangement, each thread proceeding from its bobbin 
to the machine passes through an eye at the end of a very slight wire 
lever, and the thread sustains the lever in the prescribed position so long- 
as it is unbroken ; bat if the thread breaks, the slender lever falls down 



270 PARIS UNIVERSAL EXPOSITION. 

upon another metallic surface whereby electrical contact is established, 
and a suitable bell is rung. 

"In the other machine the same effect is produced by mechanical 
means. A slender lever is sustained in its position by the thread as 
before, and this lever, in its turn, sustains a strong piece of flat iron, 
which, when let down, encounters projecting pins on the top of the 
machine, whereby a clutch situated on the driving-shaft is thrown out 
of gear, and the machine, of course, stopped. 

" In the flat machine there is a self-acting arrangement for reducing the 
width of the fabric as the machine proceeds. A lever, carrying eight 
points, or needles, arranged horizontally, facing the eight hooks at the 
extreme end of the loom, is so governed by suitable mechanism, that 
after a certain number of loops have been woven, the points penetrate 
the loops on the extreme needles, withdraw them and transfer them to 
the needles immediately adjoining, whereby these last needles have each 
two loops instead of one, and the width of the fabric is reduced corres- 
pondingly. These occasional transfers are accomplished by the aid of a 
wheel rotating beneath the machine, and armed at intervals with suitable 
projections. This wheel is advanced a tooth for each stroke that the loom 
makes, and it is only after a certain number of teeth have thus been 
passed that one of the projections comes into contact with a lever com- 
municating with the transferring points, and imparts a suitable motion 
to it. This arrangement is not new ; but the use of a segmental piece 
of steel, which raises the parts usually only sustained by small spiral 
springs, is new, whereby the fracture of those parts is prevented, even 
should any of the springs accidentally break. 

"By the use of these machines the exhibitor alleged that the process of 
manufacture is made considerably more rapid, as the machine may be 
driven at a greater speed from the less strain which is put upon the 
threads. In many of the circular stocking-looms exhibited there was an 
arrangement for altering the diameter of the woven pipe. 

"Badiguet ■ and Lecene, of Paris, exhibited several circular stocking- 
frames, in which by the aid of electricity the machine is stopped when a 
thread breaks, a lever in such event establishing electrical contact, and ren- 
dering magnetic a piece of iron which withdraws a detent and stops the 
machine. The machine is also stopped should a hole occur in the web. 
A small wheel revolves inside, and another outside the web, immediately 
beneath the knitting plane ; conduction from one of these wheels to the 
other is prevented by the intervening web, unless a hole occurs, when 
contact immediately takes place between these wheels, and the machine 
is stopped. A similar result ensues if a stitch is dropped, as in such an 
event the needle, by failing below the knitting plane, will, in its rotation, 
come into contact with a brass plate placed close below the needle-frame, 
and as both needle and plate form a part of an electrical circuit, a bell 
will be rung/' 



MISCELLANEOUS INVENTIONS. 271 



MACHINES FOR DRYING CLOTHS. 

A machine was exhibited by Mr. Tulpin, of Paris, for drying cloths, 
yarns, or other similar articles, by means of centrifugal force. In this 
there is nothing new in principle, such machines having been long in use 
for certain purposes, especially in the refining of sugar. 

A machine for steam drying, by the same exhibitor, presents, however, 
sufficient originality to merit notice. In the steam drying of cloth in 
the piece, a cylindrical drum has been usually employed, the cloth pass- 
ing round the drum while the steam is admitted to the interior. This 
construction imposes a limit to the dimensions which can be safely 
employed, unless the pressure of the steam is kept low. It limits, there- 
fore, also the degree of elevation of temperature. On both these ac- 
counts the efficiency of the machine, or the rapidity of its action, is too 
moderate to make it eminently economical. 

Mr. Tulpin's improvement is to employ an annular instead of a cylin- 
drical steam chamber. This annulus is constructed of two concentric 
cylinders, which form a closed cavity, and constitute the circumference 
of a wheel more than twelve feet in diameter. Around the circum- 
ference of this wheel, which turns slowly upon a horizontal axis, the cloth 
is carried, being kept in position by means of two endless chains, having 
tenter hooks attached. The cloth passes round nearly the entire circum- 
ference, being carried off on the same side at which it was introduced ; 
and as the velocity of motion at the circumference is but about six inches 
per second, it passes off pretty thoroughly dried. 

The construction permits the steam chamber to be made very secure 
against accident, and yet to present an exterior of quite thin metal, 
facilitating greatly the transmission of heat. The necessary strength 
is obtained by means of numerous interior stays connecting the two 
cylindrical surfaces. The steam is admitted through the axis, passing 
up the spokes. The pressure is carried as high as five atmospheres, or 
to 300° F, and upward. For the water of condensation a separate pas- 
sage is provided. It is returned to the axis and discharged by a suitable 
valve. In order that this may take place it is necessary that the annu- 
lar steam space should be divided into a number of partial steam cham- 
bers. The water which condenses in any one of these is necessarily 
carried to the top of the wheel in the course of the revolution, and thus 
returns to the axis by its own gravity. The fact of this subdivision of 
the circumference of the wheel renders it practicable to take the whole 
machine to pieces and pack it conveniently for transportation without 
any disturbance of the riveted joints. This is an advantage not only 
when there is question of conveying the machine to a distance, but also 
when it is desired to introduce it into an apartment having doors of only 
ordinary dimensions. 

It is asserted that the use of this machine is attended with a large 
economy of fuel as well as of time. This economy is stated by the in- 



272 PARIS UNIVERSAL EXPOSITION. 

ventor at not less than thirty per cent, as compared with the cost of 
steam-drying in the usual methods. 

SAFETY BRAKES FOR RAIL-CARS. 

Whatever tends to diminish the number or reduce the danger of acci- 
dents by railroad is of general interest to the public. There can be no 
doubt that many of the most calamitous of the disasters which have 
occurred within the past twenty years upon these great highways have 
been owing to the impossibility of promptly arresting the motion of a 
train after the existence of a danger had been discovered by the engine- 
driver. On European railways the passenger cars are not provided 
with brakes, In their construction, in fact, no room is left for a brake- 
man to occupy, and therefore the only means which exists for stopping 
a long train is a brake or two attached to luggage or freight vans. In 
our own country every car has its brake, and when all the brakemen are 
at their posts and operate instantly, it is possible to bring a train to rest 
within a very short distance. It is said that a train running at the rate 
of forty miles an hour has been stopped in this manner in three hundred 
and seventy-five feet. In point of fact, however, the brakemen are not 
constantly at their posts. Whenever the train approaches a regular 
stopping-place they will usually be found there ; but those are not the 
times at which dangers are most to be apprehended. It is at points 
distant from stations that broken rails, fallen rocks, landslides, or trains 
running by mistake or without authority in the opposite direction, and 
other analogous unforeseen causes of disaster, are liable to be encountered. 
In such a case it is usually the engine-driver who first recognizes the 
danger. He may signal for the brakes and reverse his steam ; but for 
a number of seconds the train will continue to advance with very little 
check to its velocity, and before the resistance can be effectually applied 
it is often too late to be of service. 

Creamer's Safety Brake. — Two inventions appeared in the Exposi- 
tion, designed to provide for emergencies of this description. Both of them 
are in the nature of automatic and instantaueous brakes to be applied 
simultaneously to all the wheels of all the cars. One of these inven- 
tions is American, and was exhibited by Mr. W. G. Creamer, of Xew 
York. It has been already introduced upon several railroads in this 
country, and experiments have been made with it in England. 

The construction and operation of Mr. Creamer's brakes will be under- 
stood from the statement that when it is employed the machinery of the 
system in common use remains unaltered, but that there is added to it a 
reserved power in the form of a closely wound and powerful spiral spring, 
which may be set free by the pulling of a trigger, and which when free is a 
substitute for the force of the brakeman. The mauner in which human 
power is applied to railway brakes is familiar to all who have travelled 
upon American roads. A chain connected with the levers which imme- 
diately apply the force to the wheels, is wound round a vertical spindle. 



SAFETY BRAKES FOR RAIL CARS. 273 

which is turned by hand by means of a horizontal wheel at the top of the 
spindle. The tension secured is maintained by means of a catch, or click, 
which the brakeman can throw in or out of a ratchet wheel with his foot. 
Mr. Creamer's spring surrounds this spindle, and is so constructed as to 
admit of being wound powerfully up, (so as to be under a tension of not 
less than twelve hundred pounds weight,) and yet to leave the spindle 
free to be operated on ordinary occasions by the brakeman as usual. 
But should a necessity arise for a sudden arrest of the motion of the 
train, the engine-driver, by a single movement, may instantaneously 
release all these powerful springs to act at once upon the several brakes, 
and the train, even when moving with the high velocity of forty miles 
an hour, will stop still in from five to ten seconds. 

The brakes may be put on not only by the engine-driver, but by the 
conductor, in whatever car he may happen to be, or even by a passenger, 
since the bell-cord which passes from end to end of the train is connected 
with the triggers, and they may all be sprung by pulling it. It conse- 
quently follows that in case the coupling of the train should give way 
at any point, the brakes would all be automatically sprung, and both 
parts of the train would immediately stop. 

Achard's electric brake. — The other form of safety brake above 
mentioned, exhibited by Mr. A. Achard, of Paris, is operated by the 
power of electro-magnetism. 

Mr. Achard supplies each carriage in the train, to the wheels of which 
his brake is applied, with a galvanic battery of six Daniell cells, which 
he has improved for this purpose. He connects these batteries with each 
other and with the engine foot-plate, by means of four wires passing 
through the whole length of the train, and properly insulated by a coat- 
ing of India-rubber or gutta-percha. By means of these electric wires 
the inventor is enabled to create two distinct electric currents, either of 
which may be closed or broken by altering the position of a handle 
placed before the engine-driver. 

In order to explain the manner in which the magnetic power may be 
brought into action in applying the brakes, it must be stated that there 
is fixed in the frame of each car carrying a brake, a transverse arbor or 
shaft extending from side to side, a little in front of and above the for- 
ward axle, upon one end of which is fixed a strong ratchet wheel. A lever 
pivoted at a point behind the axle and lying on the axle (when the appa- 
ratus is working) carries at its extremity a click which falls into the teeth 
of the ratchet. The axle has a cam at the point where the lever crosses 
it, and this cam at every revolution of the wheel lifts the lever suffi- 
ciently to advance the ratchet wheel one tooth, when a guard-click prevents 
it from turning backward. The lever is kept in contact with the axle 
and its cam by its own weight with the aid of a spring. In the middle 
of the arbor carrying the ratchet is a powerful electro-magnet, firmly 
attached to the arbor and concentric with it. Upon the two parts into 
which the arbor is thus divided by the magnet there are two loose bar- 
18 I A 



274 PARIS UNIVERSAL EXPOSITION. 

rels or drums, terminating toward the electro-magnet in circular soft-iron 
armatures. When the magnet is excited, these armatures are fixed by 
its powerful attraction, so that they and their barrels turn with it. To 
each one of these barrels is attached a chain, which, when the barrels 
are made to turn, is wound upon it, and through which the leyers are 
operated which apply the brakes to the wheels. 

From this brief account it will be seen that when the battery circuit 
which is employed to excite the magnets, is broken, the ratchet with its 
arbor may turn freely without winding up the chains, and therefore 
without affecting the brakes. But the moment the current is estab- 
lished the magnet fixes the barrels and the brake immediately begins 
to act. 

The power, therefore, which applies the brakes is actually the inertia 
of the train itself. The function which the electricity fulfils is only that 
of making a connection between the power and the work to be done. 
At every revolution of the wheels the pressure of the brakes on their 
circumferences will be increased, until the point of tension is reached at 
which the armatures begin to slip on the magnet ; after which the resist- 
ance will remain constant. The magnitude of this maximum resistance 
will depend on the power of the magnet. 

As it would not be advisable to allow the ratchet lever to rest on the 
axle, and to keep the shaft carrying the magnet constantly revolving 
when the brakes are not required, a second set of magnets is introduced, 
of which the use is to keep the ratchet levers suspended above the 
working position sufficiently high to clear the cams. These magnets are 
fixed in position, and the battery-circuit which actuates them is kept 
constantly closed, except when the brakes are applied. Then a single 
movement of the handle before the engine-driver breaks the circuit of the 
fixed magnets and closes that of the movable magnets simultaneously. 
The ratchet levers accordingly all fall immediately into their working- 
position, and the brakes begin at once to operate. At the same time, also, 
a toothed wheel, on the same arbor as the ratchet wheel, acts upon the 
apparatus of an alarm, and causes a bell to be struck in the carriage. 

Besides the handle by means of which the engine -driver puts the 
brakes into operation, each carriage is furnished with one which enables 
any passenger to do the same thing at pleasure. As a guard against the 
abuse of this power on the part of passengers, it is proposed to connect 
with the apparatus an indicator, which will show in which carriage or 
compartment the interruption originated. 

If, by any accident, the cars of a train become uncoupled, the wires 
are of course broken and the electric brakes become unavailable. 
But the ordinary brakes may in that case be applied, and these brakes 
continue to be attached to cars fitted up with Mr. Achard's improve- 
ments. Of course, from what has been said, it will be understood that. 
in this supposed case of danger, the alarm bells will necessarily begin 
to ring, so that the brakemen will be called to attend to their duty. 



SAFETY BRAKES — MECHANICAL BROOM. 275 

Moreover, since each carriage is provided with its separate battery, it 
would seem to require no great addition to the complication of the appa- 
ratus, to provide a separate circuit enabling each, in an emergency like 
that above mentioned, to work its own brake independently. 

This invention has been very favorably regarded by engineers and 
men of science whose attention has been drawn to it. The Academy of 
Sciences of France, who have a fund at their disposal for awarding prizes 
to inventors of useful contrivances for lessening the dangers and injuries 
to life or limb liable to occur in the pursuit of arts and manufactures, have 
conferred upon the inventor a prize of two thousand five hundred francs. 
Trials of the apparatus were made on the Ohemin de Fer de l'Est, in 
France, where it was applied to the express trains running between Paris 
and Strasburg, and on the Belgian State railway. The inventor laid before 
the Academy very favorable reports from the engineers of these lines, 
and Mr. Combes, the well-known Professor of Mechanics at the Ecole 
des Mines, in Paris, drew up a complete report upon the action of the 
electric brake, in the name of a scientific committee, upon whose propo- 
sition the above-named prize was awarded. 

MECHANICAL BROOM. 

A cylindrical broom designed for street sweeping was exhibited at the 
Exposition, by the inventor, Mr. Tailfer, of Paris. This machine has been 
adopted in the municipal service of Paris, and is in use in other cities of 
France. It is simple in construction, and upon well paved streets is 
very effective in operation. The broom is attached to the rear of a two- 
wheeled vehicle, by means of a framework, which is so hinged to the 
axle of the vehicle as to enable the conductor upon the box in front to 
raise it out of contact with the pavement, or to depress it for service at 
pleasure. The lever by which this is effected may be secured at the 
lowest point, so as to maintain the broom permantly raised while pro- 
ceeding to the place where the work is to be done, or when returning, 
after the labor of the day is over. 

Upon one of the wheels of the vehicle is fixed a conical gear wheel, 
which drives a pinion running on an axis inclined about twenty degrees 
to the axis of the vehicle; and this axis is connected with the axis of the 
broom by a chain working in a pair of rag wheels. The axis of the broom 
itself is inclined so as to be parallel to the axis of the pinion just men- 
tioned, and therefore oblique to the direction of movement. When the 
broom is applied to the pavement the rag chain gives it a rotation oppo- 
site to that of the wheels of the vehicle; and the dust or mud of the street 
is swept on before it and turned aside so as to form a continuous heap 
parallel to the axis of the road. 

The broom is armed with stout splints, and is sixty centimetres (two 
feet) in diameter. In length it is about 1.8 metres — say six feet. It 
leaves a track cleanly swept behind it of nearly this breadth. But as the 
heap of dust thus thrown up is moved still further on by a second broom 



276 PARIS UNIVERSAL EXPOSITION. 

following the first, or by a second operation of the same broom, it is neces- 
sary for security that the two tracks should overlap each other ; and 
hence in calculating the amount of daily service of such a machine, its 
effective track is taken at 1.5 metre. The dust and filth of the street 
having been, by successive courses of the broom, driven up to the curb- 
stone, or, by operating on both sides, to a single continuous heap in 
the middle, it is removed by scavengers' carts as usual. Observations 
on the actual performance of these machines in the streets of Paris show 
that a single mechanical broom performs the work of twelve men. The 
total cost of a machine complete is two thousand francs, the cost of the 
broom alone eighty francs. The broom, if in constant use, will require 
renewal about once a month. 

POOLET'S AUTOMATIC GRAIN WEIGHER. 

An apparatus which attracted a great deal of attention of American 
visitors to the Exposition, particularly of gentlemen from our agricul- 
tural districts, was a balance exhibited by Henry Pooley & Son, of Liver- 
pool, for weighing grain, and at the same time recording the weight of 
the grain which has been weighed. This balance, called by the inventors 
the Automatic Grain Weigher, is self-acting throughout. The only force 
employed rn the several acts of loading, weighing, discharging, and 
recording, is the weight of the commodity in process of being weighed. 
The results of any given period of work are exhibited upon the register. 

To describe the mode of action by this novel machine more in detail : 
the grain is introduced to the machine from the depot in any manner by 
which a continuous supply may be conveniently delivered into the feeder; 
then, when the first scale has received the principal part of its load, that 
scale falls through a portion of its descent, and in falling lifts a propor- 
tional weight equal to the partial load then in the scale, and at the same 
moment moves the feeder partly towards the second scale, which then 
begins to be filled while the first scale is receiving slowly the finishing 
part of its load. When the loading of the first scale is complete that 
scale falls through the remaining part of its descent, and in falling 
releases the catch that till then had held it in its position, whereupon 
the loaded scale immediately tilts and simultaneously shifts the full 
stream of grain over to the second scale and moves the register figure. 
The operation thus described proceeds from scale to scale alternately as 
long as the supply of grain is continued. The flow of grain is never cur 
off or interrupted during the discharge of the scales. 

What makes this invention specially interesting is the ingenuity with 
which a very severe accuracy in the weight of each charge is secured 
without any consequent loss of time. In ordinary weighing, if great 
exactness is aimed at, the last additions are made slowly ; and this, in 
fact, is always necessary if one would avoid inevitable overcharge. 
Accordingly, as much time is spent in adding the last few grains, or the 
last few ounces, as the case may be, as it had required to introduce the 



AUTOMATIC GRAIN WEIGHER —UNIVERSAL EVAPORATOR. 277 



great bulk of the load previously. But by employing two balances side 
by side, with a bridge, or doubly inclined shoot, between them, the inven- 
tors have made it possible to keep up a steady flow from the source, and 
still to finish oif each load by so gently growing an increase that it is 
impossible an error should occur of any sensible amount; while in the 
mean time the nearly empty scale receives the main stream and rapidly 
fills. This balance cannot fail to make its way among our western farmers, 
and among the large class of our citizens who are engaged in the trans- 
portation of grain. 

The figure will be Fig. 79. 

understood with- 
out requiring par- 
ticular description. 
The parts impor- 
tant to note are the 
two scale pans, of 
which the one on 
the right is in the 
position to receive, 
and the one on the 
left in the position 
to discharge its 
load 5 the doubly 
inclined shoot or 
bridge extending 
across above the 

Scales, and the Sup- Pooley & Sons' Automatic Grain Weigher. 

ply shoot appearing above the whole. This supply shoot is sustained 
by a branched iron support, which is single at the base, and which 
forms a vertical axis around which the supply shoot has the slight 
lateral movements above described, which change the manner of delivery 
of the grain. 

It is obvious that this balance is applicable to many purposes in which 
accurate and continuous weighing is necessary, as well as to the weighing 
of grain. 

UNIVERSAL EVAPORATOR. 

Under this name Mr. Chenailler, of Paris, exhibited an apparatus for 
accelerating the evaporation of liquids at temperatures below the boiling- 
point, which seems to be capable of useful application in many industries 
requiring a rapid concentration of dilute solutions without urging the 
temperature. Such is especially the case in the manufacture of sugar ; 
and accordingly it is stated that this apparatus has been extensively 
introduced, not only in the beet-sugar factories of France, but also among 
the planters of cane in the French colonies. The apparatus consists of a 
number of hollow disks, of lenticular figure, arranged upon a common 




278 PARIS UNIVERSAL EXPOSITION. 

axis, and dipping into the liquid to be evaporated. These disks, or lenses, 
are constructed of thin metal, and are all in communication with each 
other through the common axis, which is likewise hollow. The whole 
system is kept in slow rotary motion by some convenient moving power, 
and each disk carries up with it, adhering to its surface, a thin film of 
the liquid. As evaporation when it takes place without ebullition goes 
on with a rapidity proportional to the surface exposed, (the temperature 
being supposed constant,) it is manifest that the arrangements here 
described will increase the amount evaporated in a given time to a degree 
dependent on the number of the disks. The disks exposed were about 
a metre in diameter, and were ten in number in each set. In addition to 
the disks, one of the sets was provided with a series of longitudinal tubes 
extending parallel to the axis from end to end of the system, around the 
whole circumference. 

These also communicated, within, with the common interior of all the 
disks. The object of this communication is to allow the temperature to 
be raised, if desired, by the admission of steam, to which access is given 
through the hollow axis. 

This evaporator may be used in connection with a vacuum apparatus, 
as well as in the free air. Mr. Chenailler exhibited the arrangement 
designed for this purpose. Within a vacuum chamber of the ordinary 
description, three of the evaporating disks are mounted on an axis, 
which, passing through a packing, admit of being operated from with- 
out. For the purpose of permitting an inspection of the process, sight- 
holes are provided, protected by a strong glazing. 

In the concentration of solutions which will bear a high temperature, 
the inventor claims a very large economy for this contrivance — not less 
indeed than seventy-five or eighty per cent. " If, *' he says, " we take as 
the basis of reckoning, the fact, theoretically established, that one 
kilogram of combustible should evaporate five litres (kilograms) of 
water, I can affirm that with only the same quantity of combustible and 
the use of my apparatus, no less than eighteen or twenty litres can be 
evaporated." And this, in establishments which employ steam as a 
motive power, may be accomplished without any expense at all, if only a 
portion of the exhaust steam, which would otherwise be wholly lost, be 
made available for the purpose. 

By the aid of the ten-lens apparatus, without the extra tubes, this 
exhaust steam can be made to evaporate twelve thousand litres (four 
hundred and forty-four cubic feet, and more than threee thousand gal- 
lons) in twenty-four hours; and with the other form, the quantity 
evaporated in the same time becomes as great as eighteen or twenty 
thousand litres. It is claimed, also, that when the liquids become 
dense, a very great advantage arises from the mechanical division and 
agitation produced by the rotation of the disks. 

In the preparation of sugar this mode of evaporation is asserted to 
be productive of very sensible improvement in quality. The sugar is 



MISCELLANEOUS INVENTIONS. 279 

said to be whiter than that obtained by the usnal methods, to be larger 
in grain, and to refine with greater facility. The product, therefore, 
commands a higher price. 

It is also stated as a fact, in the description of the apparatus furnished 
by the inventor, that a number of houses which have acquired a just 
celebrity for the beauty and excellence of their sugars since the intro- 
duction of these machines, introduced them into their establishments 
originally only after having made trial by way of experiment of a sin- 
gle one of these evaporators, while continuing for the time being their 
previous methods ; but that those trials were so entirely convincing as 
to lead them to sacrifice all their old material and to replace it with 
these machines exclusively. 

In some of the notices of this apparatus which have appeared in 
industrial journals, it is stated that the invention is an old one revived. 
Whether new or old, however, it is believed not to have been heretofore 
used in the United States. 

AUBINS IMPROVED MILLSTONES. 

Mr. I. Aubin, of Paris, exhibited in Class 50 a form of millstone of 
his invention, which seems to possess some advantages to recommend it. 
A mill was also at the same time in operation to illustrate these advan- 
tages. This millstone (the lower stone) is cut through in the direction 
of the radius with several elongated or sectoral openings, which are cov- 
ered with finely woven wire gauze. The effect of this is to permit the 
escape of such portion of the flour as has been sufficiently ground, while 
the coarser particles are passed on for further grinding, and the bran is 
carried to the edge before being discharged. The bran is thus pretty 
effectually separated from the flour during the process of grinding, and 
the bulk of the flour will be found in the receptacle immediately beneath 
the stone ; while the bran with very little flour will accumulate in another 
annular receiver at the circumference. This does not of course super- 
sede the necssity of bolting entirely, in case a very fine article of flour 
is required ; but it renders bolting unnecessary for ordinary qualities, 
and it reduces very much the work of the bolts. It is Mr. Aubin's belief 
that flour is injured when the grinding is unnecessarily protracted, 
in consequence of the heat developed; and he asserts that with the 
use of his stones there is obtained both a larger weight and a better 
quality of flour from a given quantity and description of wheat than 
the ordinary mills will furnish. He claims also an additional gain from 
the diminution of the driving force consumed, in consequence of the 
relief to the mill offered by the escape of the flour as soon as ground. 
This improvement is one which apparently deserves to be carefully 
examined. 

DOOR OPENING BOTH WAYS. 

Among the inventions of minor importance exhibited, was a door 
provided with a simple mechanical contrivance for changing the hinge 



280 PAEIS UNIVERSAL EXPOSITION. 

from one side to the other at pleasure. In order to effect the change it 
is only necessary to push a knob, having the form of an ordinary door 
knob, a few inches to the right or to the left. The knob is placed in 
the middle of the door, and is connected by means of rods or bars with 
a pair of bolts at each edge or margin of the door, one at the bottom 
and the other at the top, which move vertically. The motion of the 
knob which forces one pair of these bolts outward draws the other pair 
inward. If, for instance, the bolts on the right side of the door are 
forced out, they enter into metal sockets in the door frame and form a 
hinge on that side, while at the same time the pair on the left are with- 
drawn from a similar pair of sockets, leaving that side of the door free. 
The same movement brings into place on the free side, a catch fasten- 
ing of the ordinary kind, which is commanded by the same knob which 
has operated the change. This contrivance, which would be of little 
use in the case of large apartments, may, nevertheless, be very con- 
venient where space is limited and passages are narrow. For closets, 
clothes-presses, and for doors in corners of rooms, or in places where 
several open near together, there may often be a considerable advan- 
tage in temporarily changing the hinge from one side to the other. 
The inventor is Air. H. C. Lacy, of Brighton, England. 

DOOE WITH MECHANICAL PLINTH. 

Another invention which may be classed with the last mentioned in 
regard to importance, is a door with a movable plinth, designed to 
exclude draughts, exhibited by Messrs. Jaccoux & Son, of Paris. This 
plinth is so contrived that when the door closes it shuts down closely 
upon the floor, and effectually prevents the admission of air. But 
when the door is opened, a system of springs immediately raises the 
plinth, so as to prevent friction, and keeps it raised until the door is 
again closed. The falling of the plinth is caused by a pin projecting 
from it, which strikes a metal plate on the door frame. Of course, 
when the idea is once conceived, many forms of mechanism may easily 
be contrived for accomplishing the object desired. 



CHAPTER IX. 

PROCESSES AND PRODUCTS. 

The production of steel—Puddled steel— Production op large masses by 
Krupp — Bessemer steel — Ferro-manganese — Bessemer-steel bridge— Ber- 
ard's process— Steel direct from the ore by Siemens's process — Artificial 
stone— beton-coignet — its applications — ransome artificial stone— arti- 
FICIAL fuel — Agglomerated coal— Material and manufacture of paper — 
Wood pulp— Chemical treatment — Extraction of oils by sulphide of car- 
bon — Removal of oil from wool — Robert's diffusion process for si gar — 
Enamelling and bronzing— Pleischl's enamels — Glaze for casks — Tucker's 
bronzed iron— pa-kesine. 

I.— THE PKODUCTION OF STEEL. 

Although it has been committed to other and abler hands to report 
upon the machinery and processes of mining and metallurgy which 
were illustrated in the Exposition, yet it cannot be out of place, in a 
review of industrial progress like what is here proposed, to mention, at 
least historically, the signal revolution which has taken place within 
the last twenty years in a department of production so important as the 
manufacture of steel. It is only within a period thus limited that a 
mass of this valuable material could be produced, by any known pro- 
cess, exceeding in weight two or three hundred pounds, Nothing could 
better illustrate the magnitude of the improvements which later years 
have brought than the fact that there is now hardly a limit assignable 
to the weight of the masses which are quite within the resources of the 
metallurgist. The most ponderous structures and the most powerful 
machines may now be provided, in all their parts exposed to the action 
of great forces of compression, extension, or strain, with the material 
possessing the greatest known power of resistance, and at a moderate 
expense. And the statement of the fact that this may now be done 
cheaply does not by any means tell the whole story of the progress 
which has been made, since only a few years ago the thing could not 
have been done at any price at all. 

A review of recent inventions would be singularly deficient in com- 
pleteness which should omit to mention the most important of them all ; 
and such, in view of their far-reaching consequences, must be regarded 
those which have recently so thoroughly revolutionized the manufacture 
of steel. In what follows, the object has not been to describe the pro- 
cesses themselves, whether new or old, which are employed in this great 



282 PARIS UNIVERSAL EXPOSITION. 

department of industry, but merely to give such an outline of the his- 
tory of progress as to convey an idea of the greatness of the recent 
changes. 

ORIGIN AND PROGRESS OE THE MANUFACTURE. 

The manufacture of steel is one of those industries of which the 
origin is too remote to be distinctly marked in history, yet which for 
many centuries continued to be among the least progressive of all. 
The material was originally produced, and is still in small quantities 
produced, directly from the ore; but for this purpose only a peculiar 
kind of manganiferous iron is available, which is not found except in 
limited quantities, and in particular localities. The manufacture of 
natural steel is at present confined chiefly to the island of Corsica, and 
to Catalonia, in Spain. 

Most of the steel employed for the general purposes of industry, was 
for a long time produced by a process called cementation, the immediate 
product being what is well known as bar steel, or blistered steel. This 
is prepared by exposing bars of malleable iron in contact with charcoal 
in close vessels of refractory materials, for a considerable time, to a 
high temperature. The duration of the operation varies with the cross 
section of the bars to be cemented, but it always continues for several 
days, and after its completion a still longer time must be allowed for 
the cooling of the mass before it is withdrawn from the furnace. Ten 
or twenty tons of iron may be cemented at once in a single furnace, the 
time required extendin g from twelve to twenty-two days. The bars, when 
withdrawn, are found to be converted into steel of an exceedingly brit- 
tle character, and full of fissures. Numerous cavities are found to have 
been formed beneath their superficial laminaB, presenting the appearance 
which has given to the product the name it bears, of blistered steel. In 
order to solidify it, and to restore its malleability, it is necessary that it 
should be reheated and passed beneath heavy hammers, or between 
laminating rollers; but it is very difficult, if not quite impossible, to 
eliminate all its imperfections. 

In the year 1740, a great improvement was made in England in the 
steel manufacture, by an obscure mechanic named Benjamin Huntsman. 
Huntsman's process consisted in fusing the ordinary steel, and casting it 
into solid ingots; but the method pursued by him was kept secret by its 
inventor, until at length it was disclosed by the cunning of a workman, 
who introduced himself into his shop under false pretences, and possessed 
himself surreptitiously of its details. Its general introduction proved 
to be of inappreciable advantage to all the mechanic arts. The defects 
of cemented steel, its want of homogeneousness, its numerous fissures 
and flaws, its imperfect ductility and malleability, detract greatly from 
its usefulness ; while the only means by which these defects can be removed 
or diminished, frequent reheatings and hammerings, gradually deprive 
it of the important properties peculiar to steel, and reduce it toward its 



PRODUCTION OF STEEL. 283 

original condition of soft iron. By the process of Huntsman, any descrip- 
tion of steel may be expeditiously rendered homogeneous by fusion, with- 
out impairing the qualities on which the utility of this most important 
material depends. Each operation is, however, restricted to a small quan- 
tity, and large masses can only be obtained by employing many cruci- 
bles at once. 

PUDDLED STEEL. 

About a century had passed away after the introduction of the pro- 
cess of Huntsman, when the attempt was first successfully made to pro- 
duce steel from cast-iron by the process called puddling ; the same pro- 
cess substantially by which pig-iron is rendered malleable. In this pro- 
cess the carbon in combination with the metal is gradually removed by 
oxidation, and if the process be arrested at the suitable moment, the 
product will be found to possess the properties of steel of different degrees 
of hardness, according to the degree of decarbonization. Only moder- 
ate quantities, not exceeding four or five hundred pounds, can be trans- 
formed by this means in a single operation; and in order to obtain con- 
siderable masses it is necessary to remelt the product and to combine 
the contents of many crucibles in a single casting. Much skill is required 
to conduct this operation successfully, and it can only be performed 
in large establishments, provided with many furnaces, and with mechan- 
ical arrangements such as to permit the products of all to be promptly 
brought together at the fitting moment. 

PRODUCTION OF LARGE MASSES OF STEEL BY KRUPP. 

It is about thirty years since the manufacture of steel by puddling 
began to acquire importance. The facility of the process, as compared 
with cementation, determined speedily a great advance in this depart- 
ment of industry. It was soon found practicable to produce, economi- 
cally, masses of a magnitude greatly exceeding any which had before- 
been known. The manufacturer whose successes on a large scale were 
earliest to attract attention, was Mr. Krupp, of Essen, in Prussia. At 
the Universal Exposition of 1851, this gentleman exhibited a specimen 
of crucible steel weighing nearly two and a half tons. This, however, 
was greatly exceeded in 1855, when the same exhibitor presented at the 
Paris Exposition of that year a block of the same material, five tons in 
weight But these early achievements have been thrown entirely into 
the shade by the magnificent displays of 1862, in London, and of 1867, 
in Paris, at the first of which he exhibited an ingot of twenty tons, and 
at the second, another of the enormous weight of forty tons. On this 
last occasion Mr. Krupp presented also a monster gun of fifty tons in 
weight, which, if not cast in a single piece, was only not so because it 
was necessary to shrink the external rings on to those beneath them. 
The steel employed by Mr. Krupp in this manufacture is prepared by 
puddling from the spiegel ore of Siegen. His crucibles receive from 



284 PARIS UNIVERSAL EXPOSITION. 

seventy to seventy- five pounds of puddled steel each, and are heated in 
furnaces, of which he has four hundred, capable of holding each from 
two to twenty-four crucibles. He produces more than eight hundred 
tons per week. The fractures and flexures of the massive specimens 
exposed by him near his great ingot, show the excellence of their qual- 
ity, their fine and homogeneous structure, and their remarkable tough- 
ness. 

While Mr. Krupp has thus demonstrated the possibility of producing 
steel in masses of any magnitude required to meet the exigencies of 
industry or to subserve the operations of war, the problem of economical 
production has not been so fully solved by him as could be desired. In 
the processes of puddling and remelting there is a large consumption 
both of time and of fuel. The consumption of fuel (coke or charcoal) 
approaches to, or exceeds, seven times the weight of the steel produced; 
and this is accompanied by a loss of material which is stated by Mr. 
Fremy at not less than thirty-five per cent. It must be added further 
that the process is not successful except with certain descriptions of ores, 
and that even with the purest hematites it furnishes inferior results. 

BESSEVTEK STEEL. 

The problem of producing cheap steel, of good quality and in large 
masses, remained, therefore, yet, in spite of the successes of Mr. Krupp. 
and of others whose displays in the present Exposition fairly rival his 
own. in great measure unsolved, when, about ten years ago, Mr. Henry 
Bessemer, of Birmingham, England, proposed the method, now known 
by his name, of transforming liquid iron, received immediately from the 
smelting furnace, or obtained by remelting ordinary pig-iron, at once, 
with scarcely any loss of time and no consumption of fuel, directly into 
steel. 

Mr. Bessemer was not the first to attempt the conversion of carburet- 
ted iron into steel, although he was the first to invent a practicable pro- 
cess for accomplishing so desirable an object. In the year 1848. yew ton. 
and in 1849, Marcy, patented in England methods by which they hoped 
to effect the same thing ; the principle in both cases being to oxidize out 
the carbon by directing a stream of air, or of air mingled with carbonic 
oxide, upon the surface of the liquid metal in a reverberatory furnace. 
But so long as the action of oxidizing gases is confined to the surface, 
it is quite impossible effectually to decarburize any considerable mass of 
metal, or any mass at all, except at the expense of a disproportionate 
length of time and a considerable loss of the metal itself. These meth- 
ods were therefore abandoned for others, which, though unsatisfactory 
in their immediate results, indicated very possibly to Mr. Bessemer the 
direction in which success was ultimately found. Mr. Nasmith employed 
blowing tubes to penetrate the melted mass : but instead of injecting 
air he introduced steam below the surface of the metal, having in view 
to effect two distinct objects at the same time. In the first place, by 



BESSEMER STEEL. 285 

means of the mechanical agitation produced, he aimed to effect a more 
thorough contact of all parts of the metal with the injected vapor ; and 
in the next place, by the decomposition of the vapor itself, he expected 
to furnish oxygen for the removal of the carbon from the iron, and hydro- 
gen for separating the sulphur and phosphorus. To a certain extent 
the effects anticipated were produced, but the decomposition of the 
water was attended with so large an absorption of heat, that the pro- 
cess failed through a too great reduction of temperature. To remedy 
this defect, it was proposed by Mr. IVXartien to employ a mixture of air 
and steam j and finally Mr. Bessemer adopted the plan of using air alone. 

The idea of Mr. ISasmith, of acting upon the sulphur and phosphorus 
by means of hydrogen, is one which has been more recently revived, 
and with success (as mentioned below) by Mr. Berard, and it is employed 
by him as an improvement upon the Bessemer process ; but the hydro- 
gen is generated in an independent vessel, and is not produced by the 
decomposition of water at the expense of the heat of the metal which is 
itself to be operated on. 

The Bessemer process is undoubtedly one of those remarkable inven- 
tions which from time to time transform a great industry, and exert at 
the same time an immense influence upon other industries dependent 
upon it. Like other important inventions it has had to make its way 
against the prepossessions or the prejudices of many whose opinions carry 
with them weight ; and it has had to encounter the discouragements 
which unanticipated difficulties, always sure to arise in every untried 
path, bring with them to the pioneer explorer. One by one these obsta- 
cles to the success of the new process have disappeared. It has been 
tested on a grand scale by many judicious iron-masters j and in briefer 
time by far than has been the case with the greater number of the 
improvements by which the world has been ultimately most highly bene- 
fited, its merits have been acknowledged, and it has become the life of 
an immense, a well-established, and a daily-growing industry. 

The doubts for some time entertained on the part of manufacturers in 
regard to the merits of the process of Mr. Bessemer are well illustrated by 
the language of the jury on steel manufactures, in the Exposition of 18(32. 
After stating the earnest interest universally felt in the improvement of 
the production of this, the most useful of all metals, which had mani- 
fested itself in the presentation, during the eleven preceding years, of 
no fewer than one hundred and seventy-seven applications for patents for 
such improvements in England, of which one hundred and twenty seven 
had been actually issued, the jury go on to say, " Yet out of these one 
hundred and twenty-seven patents there is only one which has brought 
about any striking change in the mode of producing steel, or which has 
been attended with any real or practical commercial results, and this is 
the process patented by Mr. Bessemer. And even Mr. Bessemer himself 
does not contemplate that the metal or steel made by his process will 
supersede the steel made in the old-fashioned way, but rather that it will 



286 PAEIS UNIVEESAL EXPOSITION. 

become a substitute for wrought irou in most cases where large masses 
of metal are required." The jury go on to state what, in their judgment, 
are the peculiar characteristics of the Bessemer metal or steel ; having 
formed their judgment partly from information received from Mr. Besse- 
mer himself and other scientific and practical men, and partly from their 
own observation and experience. They say that " when nearly decar- 
bonized it is a soft, homogeneous, useful metal, suitable for cannou, ship, 
and boiler plates, piston rods, slide bars, and generally for large forgings 
for constructive purposes; 77 but that, "when in this state it will not 
harden, and can only be welded with difficulty." Further, that "when 
a larger proportion of carbon is left in the metal, it is then difficult to 
obtain uniformity of temper or quality, and there is no certainty even 
that all the ingots from the same conversion will prove workable.' 1 

One of the members of the jury on this occasion was the eminent 
French chemist, Mr. Fremy. Mr. Fremy did not agree with his brother 
jurors ; but, in the absence of experimental data, he hesitated to press 
his opposition. He resolved to make the process a subject of careful 
personal inquiry and study, and to this end he visited first the large 
establishment erected at Sheffield, in England, by Mr. John Brown, for 
the manufacture of Bessemer steel. Here, for the first time, he was a 
witness to the conversion into steel of a mass of cast iron, two tons in 
weight, in less than fifteen minutes. This admirable operation produced 
upon him, he remarks, a profound impression; but it was not in his 
power to test the quality of the steel produced, and all his colleagues of 
the jury maintained that it was incapable of receiving a uniform temper. 
He was assured that several establishments in England had failed in the 
employment of the Bessemer process, and Mr. Bessemer himself con- 
fessed that he had been completely unsuccessful in the treatment of cer- 
tain descriptions of metal, containing sulphur and phosphorus, sent to 
him from France. Mr. Fremy left England, therefore, under the convic- 
tion that the process, though undoubtedly valuable, would never suffice 
to produce a metal which would compete with crucible steel; and as to 
the utilization of French pig-iron in this mode of manufacture, his doubts 
were more serious still. But all these doubts, he adds, were removed 
by a profound study of the process which he was subsequently enabled 
to make in a French foundry. This establishment, which had been for 
many years in existence undei^the direction of Mr. William Jackson, 
grandson of the enterprising individual by whom the process of Hunts- 
man was first introduced into France, had been created for the produc- 
tion of steel by all the known processes, and it had been the first in 
France to add to these the process of Mr. Bessemer. The opportunities 
here offered to Mr. Fremy for pursuing the investigation to which he had 
resolved to devote himself, were all that he could desire. He assisted 
at more than thirty operations. He caused the crude iron and the steel 
produced from it to be weighed in his presence, that he might determine 
exactly the loss; he studied carefully the properties of the steel pro- 



BESSEMER STEEL. 287 

duced in every case; and lie considers himself, therefore, qualified to 
pronounce authoritatively upon the value of the process itself. 

As to the nature of this process, the several steps of which it consists, 
and the modifications which must be introduced into it according to the 
character of the crude iron employed, it is not the province of this report 
to speak. These matters will be treated by the committee on metal- 
lurgy, with the professional knowledge which their discussion requires. 
For the present, it is only the results which concern us. One important 
remark of Mr. Freiny may, however, very fitly be quoted here in pass- 
ing. He says: "It had been hitherto admitted that the process of Mr. 
Bessemer was adapted to the refining only of certain silicious descrip- 
tions of iron; that it was not suited to the treatment of sulphuretted or 
phosphuretted metals; and even that our French charcoal irons would 
not develop heat enough to furnish a good product. The greater part 
of our French pig-iron was thus condemned to an exclusion which might 
be the ruin of our furnaces fed by charcoal. I am happy to be able to 
announce that this exclusion does not exist, and that our French irons, 
whether smelted with coke or charcoal, give excellent steel when treated 
intelligently in the new apparatus." 

In regard to the properties which the products of the Bessemer pro- 
cess exhibit, the testimony of Mr. Fremy is very emphatic. He says : 
"I do not hesitate to declare that the Bessemer apparatus properly 
employed pioduces true steels, and frequently excellent steels. I have 
caused the Bessemer steels withdrawn from the apparatus to be sub- 
jected, in my presence, to all the tests which characterize steel, and the 
results have been invariably satisfactory. Often the Bessemer steels 
present an assemblage of qualities appertaining at once to cemented 
steel, to natural steel, and to cast steel. They are, in fact, tough when 
cold, and uninjured by heat; they weld easily, and they can be tempered 
to extreme hardness. I preserve specimens, which were prepared in my 
presence, which demonstrate all these precious properties. Bessemer 
steels may be made at will hard or soft. Mr. Jackson often asked me 
what kind of steel I desired to obtain, and the reaction, suitably man- 
aged, gave infallibly the species of steel which I had demanded." As to 
the loss in the process, Mr. Fremy finds it rarely more than ten per cent., 
and of this loss a considerable portion may be recovered. His conclu- 
sions are summarily stated as follows: 

1. Bessemer steel, properly prepared, offers all the qualities which 
industry, or war, or the marine service, can demand of massive cast 
steel. It is homogeneous and harder and more resisting than iron ; it 
can, according to the mode of fabrication, be produced with all the 
degrees of hardness which its applications require; it is hardened by tem- 
per ; it welds and works under the hammer with more facility than 
ordinary cast steel. 

2. Bessemer steel, which is always produced at a high temperature, is 
consequently very fluid at the moment of its formation, and contains 



288 PARIS UNIVERSAL EXPOSITION. 

within its mass only a small number of bubbles. The fusion can there- 
fore give it the desired form in the first instance, and the object may be 
afterwards finished, almost without loss, by hammering and rolling. 

3. Refining for steel by the Bessemer method has become one of the 
most simple operations of metallurgy ; it is accomplished in a few min- 
utes ' y it can be committed to operatives of little skill ; it presents the 
regularity of a chemical reaction ; it does not depend in the least upon 
the dexterity or address of the workman ; it replaces all the operations 
which constitute refining for iron, cementation, and fusing in the crucible. 

4. The Bessemer apparatus gives easily, according to its capacity, 
one, two, three, or ten tons of cast steel. By combining several con- 
verters, and uniting their products, enormous masses can be obtained. 
One Bessemer apparatus of three tons will replace six or seven refining 
furnaces, nine puddling furnaces working twenty-four hours, and three 
hundred crucibles for the fusion of steel. 

5. Almost all French iron, prepared from good mineral, whether by 
means of coke or of charcoal, will give a Bessemer steel of excellent 
quality when properly treated. 

6. The consumption of combustible, which is considerable in the 
refining of pig iron, in cementation, and in fusing steel in the crucible, in 
a manner disappears in the Bessemer process of refining. The liquid 
iron can in fact be taken at the moment of its leaving the smelting fur- 
nace, and the blast can be furnished by water power. If it is thought 
more advantageous to prepare in the reverberatory furnace the metal for 
the Bessemer apparatus, it is known that the weight of combustible 
necessary will be only half that of the iron. The entire consumption in 
the Bessemer process, including the heating of the apparatus before the 
operation, does not amount to four-fifths of the weight of the steel 
obtained j whereas, by the old method, the weight of combustible employed 
is six or seven times greater than that of the product. 

These statements, in regard to the value and importance of this 
remarkable invention, are deserving of especial consideration, since they 
are the conclusions of a man pre-eminently qualified to pronounce on 
such a question, and are announced only alter a most thorough and per- 
severing study of the process in all its phases. Since the publication 
of this report of Mr. Eremy, the Bessemer steel industry has received 
a much larger development than it had then acquired ; and this is rapidly 
growing in every direction. In England, France, Sweden, and Austria, 
large quantities of the metal are annually produced, and the manufac- 
ture has been commenced in Prussia. Beautiful Specimens are pre- 
sented in the Exposition from all these countries. From the Arias Works 
of Sheffield, England, belonging to John Brown & Co.. are exhibited 
steel tubes for cannon nearly ten feet in length, and more than a foot in 
diameter, beautifully finished in the lathe, and showing a perfectly uni- 
form, homogeneous, and compact structure. The same manufacturers 
exhibit also projectiles, spherical and elongated, of great size. The 



BESSEMER STEEL. 289 

spheres are finished under the hammer, and one of the largest weighs 
one thousand one hundred and thirty-six pounds, with a diameter of 
twenty inches. 

Of steel plates for ship-building and other jmrposes, many thousand 
tons have been rolled in England during the last few years. A single 
firm in Sheffield (not represented at the Exposition) has prepared more 
than five thousand. The London journal, " Engineering," states that 
another firm is prepared to take orders for any quantity of Bessemer 
steel plates up to sixteen hundred- weight each, of which the sheared 
edges shall double over cold under the hammer without the slightest 
crack. Some of their plates, thirteen feet long, six feet four and a half 
inches wide, and seven-sixteenths of an inch thick, which though large 
are not of the largest size, are said to have given excellent results. 

AUSTRIAN AND SWEDISH EXHIBITIONS OF BESSEMER STEEL. 

The Austrian and Swedish exhibitions of Bessemer steel are particu- 
larly interesting, as furnishing illustrations of the variety of quali- 
ties which may be imparted to the metal by variations in the treatment 
during conversion. The government iron works at Neuberg have pre- 
sented bars, plates, ingots, and manufactured articles, of this material, 
many of which have been subjected to flexure, fracture, and torsion, in 
order to show their toughness, soundness, and homogeneousness of 
structure. Some of these articles also bear a high polish. Seven dif- 
ferent descriptions of metal are prepared at these works, which are 
classified and numbered according to the amount of carbon which they 
contain ; No. 1 being the hardest, and No. 7 the softest. 

At the Fagersta Works, in Sweden, the varieties are much more 
numerous; careful tests having been made not only by flexure, tension, 
and torsion, but also by compression, of specimens differing from each 
other by one-tenth of one per cent, of carbon, from 1.3 per cent, down- 
ward, and extended below 0.1 to almost absolute decarbonization. The 
behavior of the specimens submitted to compression is very striking. 
They are all more or less diminished in height, the softer by more than 
one-half 5 and yet no one of them has been crushed, or has betrayed any 
tendency to fracture on any part of its circumference. The effect of 
torsion is shown upon cylindrical bars, by the appearance of lines 
drawn on their surface originally parallel to the axis, but which have been 
converted, by the process of twisting, into spirals of beautiful regularity. 

Bessemer steel from Austria is exhibited by two manufacturing estab- 
lishments, and by the Southern Eailroad Company of Styria. Among 
the specimens is a block made at a casting from a single converter, of 
three tons in weight. There are also boiler plates which show remark- 
able tenacity on being bent cold. 

Not a single specimen of Bessemer steel is presented from Germany. 
This is attributed by some to the continued existence in that country of 
19 i A 



290 PARIS UNIVERSAL EXPOSITION. 

the prejudice against which this invaluable invention has had to contend 
everywhere, but which has been, in great measure, overcome in France, 
England, and America, by the overwhelming and daily accumulating 
evidence of its merit. Moreover, the German producers, and especially 
the Prussian, having become pre-eminently distinguished for the magni- 
tude and the excellence of their crucible steel manufacture, they cannot, 
without a natural reluctance, yield the palm in this magnificent con- 
course to those of any other nation j and they are, therefore, likely to be 
the last to adopt a process which may possibly at some day supersede 
that which they have themselves created, and which in their hands has 
produced so magnificent results. But by some, also, it is in no small 
measure attributed to a less worthy cause, and that is, the disposition 
to profit by the invention by availing themselves of the inadequate pro- 
tection afforded by the German patent laws to the rights of the inventor, 
while they decry the invention itself in order to cover up this ungener- 
ous practice. The editor of the journal above cited says : " The Besse- 
mer steel makers in Germany pay no royalty to the inventor, and they 
are, therefore, not allowed to import their products into France, Eng- 
land, or any other country where Mr. Bessemer's patents are valid. It 
is, therefore, obviously to the advantage of these steel makers to keep 
their mode of manufacture a secret, i. e., to deny that their steel is made 
in accordance with any patented plan, and thereby to secure to their 
products the possibility of importation into other countries without the 
payment of royalties. This being the case, the inducement to create 
prejudice against the quality of Bessemer steel, as compared with what 
is called 'cast steel,' or 'crucible steel,- 1 is very great; and the conse- 
quence is that, out of a considerable number of establishments in Ger- 
many who produce Bessemer steel in large quantities, and of excellent 
quality as well, there is not one at the Paris Exhibition which uses the 
name of Bessemer for the products exhibited. We do not think that to 
be a just and fair mode of treating an investor who has conferred so great 
a benefit upon the iron manufacturers of all countries." Xo, it is by no 
means just or fair, but it is the kind of justice and fairness which great 
inventors usually receive at the hands of their contemporaries. Mr. 
Bessemer has, in fact, been quite exceptionally fortunate. His rights 
have been respected in his own country and in some others, and he reaps 
a corresponding advantage. It has too often been the case that great 
inventors have not only been stripped of their rights, but have been left 
to starve among the people for whose benefit they had impoverished 
themselves. Such was the reward of Leblanc for the greatest discovery 
of his age in applied chemistry. Such came very near being that of 
Watt, for the most important mechanical invention ever made. 

The importance of the new process for steel will not so much appear 
if, in considering the greater cheapness and facility with which the metal 
can now be produced, we regard those purposes only to which it has 
hitherto been applied, as when we turn our attention to the vast variety 



BESSEMER STEEL — FERRO-MANGANESE. 291 

of new uses for which it will hereafter be in continual demand. Iron, 
up to the present time the most valuable of all the metals, for the variety 
of its applications, fulfils, after all, but imperfectly many of the func- 
tions to which it is applied only because there is uo better economically 
available. In the form of cast iron it is hard, but brittle ; in the form of 
wrought iron it is tough, but soft. In either case it is deficient in elas- 
ticity. Steel possesses all the good qualities of iron in both its forms, 
and to a greater degree than either, while it has additional and no less 
valuable qualities which are not found in wrought or in cast iron. 
Nothing but its cxpensiveness has prevented it from being long since 
applied to the construction of all parts of machines which are to be sub- 
jected to strain or to constant friction ; to the construction, for instance, 
of axles, of wheel-tires, of wheels themselves, of piston rods, of steam- 
engines in all their parts, of boilers, of propeller shafts, of fire-arms of 
all kinds, and especially of heavy guns, of armor for ships or for fixed 
batteries, of the hulls of ships themselves, of railroad machinery and 
rails, and of a multitude of minor objects important to industry which 
it is needless to enumerate. The very moderate prices at which Besse- 
mer steel can be furnished cannot fail to cause it soon to take the place 
of iron for most of these purposes. It is obvious, from the mode of its 
manufacture, that, so far as the expense of labor and consumption of 
fuel are concerned, it can be produced even more cheaply than iron. 
Moreover, the peculiar manganesic ores, occurring only in certain locali- 
ties, which have hitherto been found most advantageous, and to a cer- 
tain extent indispensable, for manufacturing good steel by any process, 
have been satisfactorily and very simply replaced by Mr. Bessemer, by 
means of a manganesic iron artificially prepared. 1 No natural or eco- 

1 It appears that the manufacture of this product, so interesting and valuable, after having 
been commenced under promising auspices, has been, at least for the time, suspended. The 
following statement, taken from the London "Engineering," explains the circumstances : 

"In the history of the Bessemer process the name of ferro- manganese will, under all cir- 
cumstances, have an important place. Though the manufacture of this substance has now 
been interrupted, or perhaps finally givea up, by the parties who first succeeded in making 
it, practically and commercially, and may have proved unprofitable as far as the past and 
present state of the market, and of the steel manufacture, is concerned, there can be no 
doubt that with the further extension of the Bessemer process, and with the application of it 
to the manufacture of the softest kind of steel or malleable metal, such a substance will have 
to be again brought into the market, and it will ultimately find its place among the metal- 
lurgical products of every-day use in steel-making by almost all modern processes The 
manufacture of ferro-manganese was commenced, at Mr. Bessemer's suggestion, by Mr. 
Henderson, of Glasgow, who invented and patented a process for the production of alloys of 
iron and manganese, containing a high percentage of the latter metal. A Siemens furnace 
was erected for carrying out this process at the Phoenix Foundry, Glasgow, about three years 
ago, and the manufacture of ferro-manganese was commenced with apparently good com- 
mercial results, and certainly with the greatest success, as far as the quality of the product 
was concerned. The metal has a price in the market depending upon its percentage of 
manganese, the steel-makers paying £1 per ton of ferro-manganese for each per cent, of 
pure manganese contained in it. A ton of ferro-manganese, for example, guaranteed to con- 
tain twenty-three per cent, of manganese, was sold at £23 and at that price it was upon a 



292 PARIS UNIVERSAL EXPOSITION. 

nomical obstacle, therefore, can any longer exist to prevent the substi- 
tution of steel for iron on a scale as extensive as the best interests of the 
industrial arts may require. And even supposing that, weight for 
weight, steel should for a time continue to be more expensive than iron, 
it must not be forgotten that it will always possess two especial advan- 
tages which may make it cheaper in the end, and possibly cheaper, also, 

par, as far as manganese is concerned, with the average of German spiegeleisen which (con- 
taining about seven per cent, of manganese) stood at £7 in the quotations of iron-merchants 
n this country. 

" The mode of manufacture, as carried on in the Phoenix Foundry, consisted in mixing 
carbonate of manganese, a substance obtained in soda works as one of the products of the 
manufacture of bleaching powder, with an almost equal quantity of a pure calcined iron ore, 
also drawn from a soda works, in which it formed a kind of refuse. The original substance 
which yields this iron ore is a kind of iron and copper pyrites, found in large quantities on 
the south coast of Spain." 

After describing the method of separating the sulphur and copper, leaving the oxide of iron 
purified from all its admixtures, and in a state of mechanical aggregation very suitable for 
reduction, the writer proceeds : " This iron ore, obtained as a residuum or waste product from 
the copper works, was the second raw material employed by Mr. Henderson for making 
ferro-manganese. The two substances, viz., carbonate of manganese and oxide of iron, 
were mixed with charcoal powder or coke dust, and the whole mass charged without crucibles 
into the Siemens furnace. The reduction of both metals, iron and manganese, took place 
simultaneously, and the percentage of manganese increased with the temperature, but not 
with the quantity of manganesic matter put into the charge ; all surplus of the latter going 
into the slag and eating through the fire-bricks of the furnace in a remarkably short time. 
This destruction of bricks by the chemical action of the manganese slag was. in fact, the 
great difficulty in this process. It went so far that the powder carried into the regenerators 
by the current of gases, and afterward heated when in contact with the bricks, melted and 
destroyed even these portions of the furnace, and necessitated frequent repairs. The bottom 
of the furnace was lined with graphite, and this stood better than the exposed surfaces or 
the fire-bricks in the other portions. The metallic alloy of iron and manganese produced, 
ranged in its percentage from seventeen to thirty per cent, of manganese, and it was very 
free from other impurities. The Bessemer Steel Works employed it for the manufacture ot 
the softest articles, such as boiler plates, &c, but its high price prevented its use for the 
manufacture of rails, and consequently the demand for it remained smaller than was origi- 
nally expected. The manufacture of this metal has, therefore, not been continued at the 
Phoenix Foundry, and consequently this useful and valuable material does not at present 
exist in the market. Steel-makers are now entirely dependent upon spiegeleisen for the 
necessary supply of manganese; and although they have succeeded in making the spiegel 
give sufficiently good results, there still remains an acknowledged want of a richer manganesic 
alloy ; and this will probably make itself felt all the more when the attention of Bessemer 
steel-makers is more largely turned to the manufacture of armor plates." 

The following is one of the methods which have been practiced by Mr. Bessemer himself in 
the preparation of ferro-manganese for the uses of his own works. He has been accustomed 
to melt iron of the purest qualities, and to granulate it, when melted, into shot, by pouring it 
upon a revolving wheel throwing the particles into cold water. This small iron shot is then 
placed in a crucible, or in a reverberatory furnace, along with a powdered mixture of very fine 
anthracite coal and black oxide of manganese, and subjected to heat. The heat which will 
decompose the oxide of manganese is always sufficient to melt the iron, and to form a perfect 
mixture of the two metals. The anthracite, of course, goes to carburize the oxygen of the 
oxide, and passes away, thus leaving a comparatively pure ferro-manganese. With this 
compound any required amount of manganese may be introduced into a " blow" of Bessemer 
steel, and that without at the same time adding a hurtful proportion of carbon, which is too 
often the case in the use of spiegeleisen. 



BESSEMER STEEL. 293 

in tlie beginning ; for the relative strength of the two materials is so 
greatly in favor of steel, that the weight of every heavy article in which 
it replaces iron may be considerably reduced, thus securing an economi- 
cal and a mechanical advantage at the same time. 

STEEL RAILS. 

The durability of steel so much exceeds that of iron, that the 
expense of maintenance of any construction in which it is employed will 
be greatly diminished. These advantages are illustrated in the experi- 
ence of the Northern Railway Company of Austria, which was one of the 
earliest to experiment upon rails of Bessemer steel, and which exhibits 
specimens of its rails in the Exposition. These rails were at first 
employed by this company only by way of trial upon the most frequented 
parts of their line. The results proved so satisfactory as to induce the 
company to lay them down over the whole line. Seventeen miles laid 
down a year ago (1866) as yet show no signs of wear. Two hundred 
and fifty miles additional were ordered in 1867. But the results of the 
experiments made were not merely satisfactory in regard to the increased 
durability of the new material. They demonstrated that the section 
might be materially reduced. With a weight per yard of only forty-five 
pounds, the company obtained a steel rail having double the strength of the 
iron rails of larger section previously employed by them. The cost to the 
company per ton of iron rails having been from sixty dollars to seventy 
dollars, and that of steel rails being from ninety dollars to one hundred 
dollars, the expense per running mile is still kept nearly within its 
original limits, Avith a very great improvement in regard to strength 
and durability. 

The French railway companies are also extensively introducing rails 
of Bessemer steel upon their roads. These rails, as manufactured at the 
principal French works, cost from sixty dollars to seventy dollars per 
ton. 

BESSEMER-STEEL BRIDGE. 

The largest single construction of Bessemer steel yet made, (1867,) so 
far as the information of the present reporter extends, is, however, the 
bridge on the Quai D'Orsay, beneath which communication is estab- 
lished between the Exposition on the Champ de Mars and the Berge on 
the Seine. This bridge is a single arch, twenty-five metres (eighty-three 
feet) in span, and two hundred and seven metres (six hundred and fifty- 
eight feet) in breadth. The arch is formed of eleven parallel ribs, which 
are connected with a corresponding number of horizontal girders above 
them by means of a lattice-work patented by Mr. Joret, the constructor. 
It is the archway only which is constructed of steel, the structure 
immediately sustaining the road being of iron. The following interesting 
particulars in regard to this bridge are taken from a notice in the 
London journal, Engineering: 



294 PARIS UNIVERSAL EXPOSITION. 

"The bridge was tested before being opened for traffic with a load of 
five hundred kilograms on the square metre, or one hundred and two 
and a half pounds per square foot of its surface, under which test the 
deflections were carefully measured, and were within the limits given by 
the calculation. A further test has been made by two wagons loaded 
with twelve tons on one pair of wheels, and drawn by five horses each, 
these being drawn forward and backward, the deflections being at the 
same time measured by means of thirty gauges placed at different points 
under the bridge. The mean deflection under this load never exceeded 
seven millimetres, or hardly more than one-fourth of an inch, leaving 
no measurable permanent set, and the bridge was opened by the gov- 
ernment authorities to public traffic 'without reserve,' i. e., the bridge has 
been proved strong enough to carry any load which ordinary road traffic 
can bring to bear upon it. The traffic has never since been restricted 
or stopped, and no signs of weakness have shown themselves. The 
bridge is fixed in its place temporarily only, as it has been constructed 
for another place, to which it will be removed after the close of the Exhibi- 
tion, and it is therefore put together in all its principal joints with screw- 
bolts, which will afterwards be replaced by rivets when the bridge shall 
be erected at the point of its ultimate destination. The construction is 
on the patent principle of Mr. H. Joret, of Paris, one of the contractors 
for the Exhibition building. Its peculiarity consists in the mode of con- 
necting the arch and the straight girders which carry the roadway by 
means of lattice-work riveted to prolongations of the central web. 

"The lattice-work and the superposed structure are made of iron, since 
the sections of these parts are already sufficiently reduced to allow of 
no further reduction by the application of steel; but the carrying parts 
of the structure, i. e., the arches, are made completely of Bessemer steel, 
rolled at the Terre Noire Works, Loire, in France. These works belong- 
to a company who possess extensive mining property in several localities 
in France, and have a good reputation for the good and uniform quality 
of the steel produced, and they have principally laid themselves out for 
rolling plates, flats, angle steel, and rivet steel, the materials for bridge 
construction and civil engineering works, while the other Bessemer 
steel works in France have devoted their operations more especially to 
the production of railway material and of forgings of great weight. The 
calculated maximum strain brought upon the Bessemer steel under the 
test load is ten kilograms per square millimetre, or 6.3o tons per square 
inch, while the experiments previously made with this material showed 
that a load of twelve kilograms, or 7.62 tons, per square inch, would be 
fully admissible, and within the limits of safety. 

"The arch consists of eleven ribs, or principals, connected with the 
straight girders above, which carry the level roadway by means of Mr. 
Joret's lattice-work, which allows of a reduction in the sizes and sections of 
these bearings, on account of its distributing the load upon a greater 
number of carrying points than is usually reached. The structure has 



BESSEMER STEEL BERARD's PROCESS. 295 

a very light and graceful appearance, and is considered very economical 
in point of material and work. Mr. Joret has applied the same principle 
to several other bridges built by him in France and abroad, among 
which is bridge at Sennecey, over the Saone, in five arches of one hun- 
dred and fourteen feet ten inches span each, the bridge at fipierre, over 
the Arc river, in Savoy, and the bridge of Valvins, over the Seine, near 
Fontainebleau, in five arches of seventy-two feet one and a half inch 
span each." 

BERARD'S PROCESS. 

Since the introduction of the Bessemer process no step of advance 
has been taken in the progress of steel manufacture which can compare 
with it in importance. Some valuable modifications have, however, 
been introduced into it, having in view the object of eliminating from 
the iron the elementary substances which are so often combined with 
it, and of which the effect is in general to injure the quality of the final 
product. These, which are sulphur, phosphorus, arsenic, and silicon, 
are, like the carbon, oxidizable, and are, therefore, in a measure, removed 
in the process of conversion. The elimination might be carried further 
by prolonging the period of oxidation, but the effect of this would be 
to decarburize the metal too considerably, and also to oxidize a quantity 
of the iron itself, which would be at least proportional, and might be 
more than proportional, to the quantity of the injurious substances 
removed, so that the metal remaining would not be improved in quality, 
and might even possibly be injured. 

It is, however, well known that the affinities of sulphur, phosphorus, 
and arsenic for hydrogen are very great, while hydrogen at the same 
time reduces iron oxides. And it is further true that the compounds 
formed with hydrogen by the substances above named are gaseous at 
ordinary temperatures. These considerations suggest the advantage of 
acting upon the liquid metal which has been sufficiently decarburized 
either in the puddling process or in the process of Mr. Bessemer, by 
means of a stream of pure hydrogen gas, or, since that would not be 
economical, of mixed and compound gases in which hydrogen predomi- 
nates. This is the principle of the process introduced Mr. Berard, already 
mentioned in another part of this report, which he applies in a puddling 
furnace of peculiar construction on the general plan of tbat of Mr. 
Siemens. This furnace has two independent hearths, separated by a 
bridge, and the flame enters alternately on one side and on the other. 
The oxidation is effected by introducing into the metal, when the fusion 
is complete, plunging tuyeres which blow the air through it as it is blown 
through, somewhat differently, in the Bessemer converters. A tumultuous 
agitation takes place during this part of the process; drops of metal are 
thrown up which oxidize in the air, and falling back are more or less 
reduced again. The hearth itself becomes excessively heated, and in 
this way stores up a supply of heat to be expended in the subsequent 



206 PARIS UNIVERSAL EXPOSITION. 

reducing process. At the end of ten minutes the flame is reversed, and 
the plunging tuyeres being withdrawn from the metal thus far acted on, 
another set are introduced into that upon the second hearth. 

It will be understood, from the relative situation of the two hearths, 
that the flame, from whichever side it enters, acts upon both hearths 
successively: but that it expends its oxidizing power on the first, and 
becomes on the second a reducing flame. The effect, however, of the 
superficial contact of this flame upon the metal is not alone relied on, 
but plunging tuyeres are employed to force reducing gases through the 
mass, in the same manner as that in which the air was introduced pre- 
viously. These gases consist of a mixture of carburetted hydrogen, 
oxide of carbon, and hydrogen pure. They are generated in a special 
apparatus, in part by the decomposition of superheated water, and are 
carefully purified. Before reaching the tuyeres they pass through a 
heating apparatus where they are raised to a high temperature. 

The action of the gases is not simply a volatilization of the injurious 
elements. There is also a greater or less absorption of carbon by the 
metal ; and this can be varied by employing mixtures of the gases in 
different proportions. There results from this fact the important advan- 
tage that the process may be accelerated or retarded according to the 
length of time which may experimentally be found necessary to get rid 
of the impurities in a given description of pig-iron, without either decar- 
burizing too far the product, or increasing the waste of material. TVith 
gray cast iron of medium quality the whole operation, for a mass of two 
or three tons, lasts from half an hour to three-quarters. The oxidizing 
and reducing operations alternate at intervals of from ten to twelve min- 
utes. When the purification is complete the excess of carbon in the 
metal is removed by oxidation, either by adding pure oxide of iron or 
by the action of the air. The state of advancement of the process is 
tested from time to time by taking samples. 

One great advantage of this form of furnace and of this process is, that 
the process is continuous, the charges on the two hearths being brought 
alternately to the completed condition, drawn off and replaced by fresh 
charges, without interrupting the operation ; and while both hearths 
are occupied, the bridge intervening affords a convenient place for heat- 
ing the pigs in advance of their introduction into the furnace. 

In the use of this process, it is affirmed, by those interested in it, that 
a single furnace will turn out fifty or sixty tons of steel a day : and such 
a furnace, placed in connection with a smelting furnace, from which it 
may receive the liquid metal directly, will, according to the same au- 
thority, furnish steel in ingots cheaper than iron. The loss in the pro- 
cess is stated not to exceed eight or ten per cent. 

There are claimed for the steel produced by this process qualities supe- 
rior to those of ordinary Bessemer steel. It is perfectly homogeneous. 
fine grained, soft before temper, tempers very easily, and may be made 
remarkably hard. It also bears reheating uncommonly well. In a series 
of experiments made by Mr. Charpentier, of Montataire, it showed no 



PRODUCTION OF STEEL SIEMENS'S PROCESS. 297 

sensible change after ten repetitions of this process with intermediate 
tempering. After the first experiments its density increased, till it 
became at length 8.92, a density which has not been before attained for 
steel. 

PRODUCTION OF STEEL FROM THE ORE BY SIEMENS'S PROCESS. 

Mr. Siemens himself has also recently patented a mode of applying his 
furnace to the direct production of steel from the ore. He exhibited a 
specimen of the steel so produced in the Exposition. The following out- 
line of this plan is taken from the London Engineering: 

" The furnace is constructed somewhat similar in form to the Bachette 
furnace, viz., with two parallel sides sloping downwards, so as to form 
a kind of trough between them. The ore is charged at both sides on the 
top of the furnace, and slides down the inclined planes of the two sloping 
sides. At the bottom of the furnace the gases from the producer and 
the necessary supply of air are admitted, and produce an intense flame, 
the products of combustion rising upwards through the masses of ore, 
which are acted upon in a similar manner to that in the blast furnace. 
With very pure manganesic ores it is possible to manage the process so 
as to decarburize the newly produced iron immediately after it is made, 
or rather the heat can be made sufficient for melting a metal which con- 
tains less carbon than common cast iron as made in the blast furnace, 
and at a lower temperature. This metal is natural steel, or 'raw 7 steel 
and, made from ores of sufficient purity, may have all the qualities of 
the best cast steel. The specimen exhibited by Mr. Siemens, and made, 
we understand, at his Model Steel Works in Birmingham, where the 
first experiments with this new process have been carried out, is of very 
fair quality as far as can be judged from its general appearance and 
fracture. We have been informed that Mr. Siemens is now erecting a 
similar furnace at Barrow-in-Furness, intending to make steel from 
hematite ore direct, at the Barrow Steel Works. Mr. Siemens's new pro- 
cess, if successful and economical, would do away with blast furnaces, 
and all other processes for making and refining iron now in use ; but it is 
too little advanced at this moment to allow of a judgment of the proba- 
bility of its practical success, to say nothing about relative economies. 
Its practicability remains to be established. But if we consider how 
much the same inventors have already established, how difficult it was 
to believe in the success of the Siemens furnace itself when first brought 
out, and how completely they have succeeded in this respect, we may be 
justified in entertaining some hope that this new invention will ulti- 
mately prove equally successful, although at present it may appear very 
revolutionary and contrary to adopted notions." 

Considering the rapidity with which, during the last twenty years, 
improvements have followed each other in this most important branch 
of productive industry, it is not too much to predict that the time is very 
near at hand when the manufacture of steel directly from the ore will 
have superseded all other processes. 



298 PARIS UNIVERSAL EXPOSITION. 

II.— ABTIFICIAL STO^E. 

In reviewing the useful inventions of comparatively recent date, it is 
impossible to overlook the great advances which have been made within 
a very few years in the artificial production of a material which, for the 
ordinary purposes of architecture, and eveu, to a certain extent, for the 
uses of higher art, possesses all the qualities of durability and beauty 
which belong to natural stone. No visitor to the Exposition of 1867 
could have failed to be struck with the large number and variety of 
objects, frequently extremely elegant, which presented themselves on 
every side, but especially in the French and Prussian sections of the 
park, formed of what is called beton agglomere, or with the still more 
beautiful objects in the English section, made of the artificial marble of 
Mr. Eansome. 

BETON AGGLOMERE. 

As to the class of objects first mentioned, the admiration of most visit- 
ors could not but have been mingled with some surprise, on learning 
that the material which exhibited such hardness and solidity and great 
specific gravity, and in its exposure to the weather during the several 
months that the Exposition lasted gave evidence of being so unalterable 
under atmospheric influences, was yet, so far as its composition is con- 
cerned, nothing more than common mortar with lime in very small pro- 
portion to the sand, and sometimes (not always) with a small addition 
of hydraulic cement. It differs from mortar only in being mixed in the 
preparation with a great deal less water, and being compacted by heavy 
ramming. 

The agglomerated betons have been extensively introduced in France 
in the construction of heavy public works, and in the erection of private 
dwellings. Nearly forty miles of the sewers of Paris have been constructed 
wholly of this material. All the foundations and basements of the 
palace of the Exposition, and other heavy structures in the Champ de 
Mars, those of the immense military barrack recently erected on the 
island of the city, the railroad bridge of Ste. Colombe on the road from 
Lyons to Marseilles, a very large number of substructures for private 
houses, some houses entire, and innumerable foundations for the support 
of heavy machinery, have been constructed in the same way. 

The manufacture as now generally practiced was originated by Mr, 
Coignet, a French engineer, whose name is generally associated with the 
process. The following particulars in regard to the Coignet beton are 
gathered from several sources, the most interesting being derived from 
a paper on the subject, published by Mr. A. Paul, civil engineer of Paris. 

This substance is compounded of sand in large quantity, with lime in 
smaller, say in the proportion of five to one, more or less, and also, if 
rapid setting and unusual hardness are desired, with a quantity of 
cement, hardly more than one-quarter of the quantity of lime, the pro- 



BETON AGGLOMERE, COIGNET's PROCESS. 299 

portions being estimated by volume and not by weight. This mixture, 
in a condition nearly dry, and reduced to the form of a stiff paste, by 
being ground and worked up in mills constructed for the purpose, is 
introduced into the moulds designed to give it form, and compacted by 
repeated blows of a heavy rammer. The result is the production of a 
copy firm enough to allow the removal of the mould at once, by the sepa- 
ration of its parts. The copy is perfect, since the yielding material, 
under the heavy impact of the ram, has been driven into all the minute 
lines of the mould, and all the delicate traceries of the ornamental work. 
On exposure to the air the block rapidly hardens, and it has soon all the 
solidity of natural stone. 

The effect of the successive processes of grinding and ramming is 
singularly to increase the specific gravity of the product. The reduction 
of volume, when the bulk of the compacted mass is compared with that 
of the materials out of which it is composed, is nearly as two to one, 
(1.7 to one,) and the weight per cubic foot becomes about one hundred 
and forty pounds. Simultaneously with the increase of weight, there 
occurs a very remarkable increase of strength ; the resistance of many 
specimens to compression amounting to more than two and a half tons 
to the square inch. 1 An ordinary mortar made with precisely the same 
materials will be crushed by a pressure of probably less than five hun- 
dred pounds. 

The explanation of this greatly increased cohesive strength may per- 
haps be found in the following considerations : 

In mixing mortar an excess of water is always employed, and this 
occupies much space, and by separating the molecules of lime prevents 
their union, or acts unfavorably to what is called the setting of the mor- 
tar. If we suppose this setting, in the case of lime or of cement, to be an 
actual, though perhaps confused, crystallization, whether of hydrate of 
lime, or of the silicate and aluminate of lime, mixed or combined, which 
constitute, in different proportions, hydraulic limes and cements, it fol- 
lows that this crystallization will be so much the more energetic in meas- 
ure as the water present in the mortar in excess during the preparation 
is more effectually eliminated, and that in the same proportion the 
union of the sand, lime, and cement will be more intimate. 

It is the opinion of the engineer whose paper has been cited above, that 
the hardening of the compacted mass is not exclusively due to the phys- 
ical properties of the lime and cement in their original condition, but 
is owing also, in a measure, to the conversion of these substances gradu- 
ally into carbonates, and that this conversion goes on the more rapidly 
and becomes the more complete in proportion as the lime is more finely 
divided. 

Hydraulic lime should be used in this preparation. Fat lime may be 
employed, provided that a sufficient proportion of cement be added to 

1 Specimens of very superior betons have even resisted crushing pressures approaching to 
four tons per square inch of section. 



300 PARIS UNIVERSAL EXPOSITION". 

give it the hydraulic character. The lime should be well burned ; lumps 
which seem to be overbumed or uiiderburned must be rejected. It is 
slacked by sprinkling, and afterwards heaped up and allowed to lie some 
days in order that it may acquire its maximum of volume and become 
thoroughly disintegrated. It is then sifted through No. 35 wire gauze. 
In this powdered condition the slacked lime may be kept for lengths of 
time. 

It has been proved by the inventor, Mr. Coignet, that all kinds of 
lime, even the most common, after a while become as hard as the best. 
The only difference is in the promptness of the setting. In explanation 
of this fact, it is suggested that the ultimate hardness is probably due 
to the formation of the carbonate. 

The cements employed in the manufacture of these betoris are in gen- 
eral the heavy and slow setting cements. The sand preferred is river 
sand, mixed with particles of stone of from one to five millimetres 
in diameter. If the sand is too coarse, the resulting masses will be 
rough • if too fine, it separates too much the molecules of the lime, retards 
the setting, and is prejudicial to the strength and durability of the 
resulting product. Pit sand answers very well; but in order to produce 
a result equal to that obtained with river sand, it is necessary to 
increase the proportion of lime and cement. 

In mixing the materials, they are rudely measured, spread out on the 
ground, and turned with a shovel until the mass becomes homogeneous. 
They are then introduced into a tempering mill, and subjected to a very 
energetic grinding; water being added sparingly from time to time, and 
only in sufficient quantity to give the mass cohesiveness, and bring it to 
the form of a paste as stiff as can be conveniently worked. The import- 
ance of this part of the operation is very great, since the rapidity of 
the setting and the degree of the ultimate hardness will depend upon the 
minute subdivision, which is the effect of the grinding in the mill, of the 
particles of lime and cement. 

The tempering mill is one which has been constructed specially for 
this purpose. It is of rolled iron, cylindrical in form, and has a vertical 
arbor in the centre, armed with knives set spirally around it. At the 
bottom the cylinder is perforated with many holes, through which the 
material is expelled by the pressure of a cycloidal appendage attached 
to the arbor below the knives. The rapidity of the expulsion may be 
controlled by raising or depressing a cylindrical gate, resembling the 
gate of the Fourneyron turbine, the process being retarded as the num- 
ber of holes uncovered is diminished. As the tempered beton is expelled 
in the plastic condition at the bottom, additions are made to the 
quantity in the mill, by introducing raw material at the top. 

The plastic beton thus obtained is thrown into the moulds in strata 
of from one to three inches thick, and beaten down and compacted by 
repeated blows of a heavy ram, weighing from fifteen to twenty pounds, 
applied all over the surface. The beating of a stratum having been com- 



USE OF BETON IN BUILDING. 301 

pleted, its surface is scratched and roughened by means of a rake, for 
the purpose of forming a secure bond with the stratum next to follow. 

Two kinds of moulds are employed, according as the object moulded 
is to remain permanently in the spot where it is formed, or is to be 
removed and built into a structure elsewhere. In the first case, the 
moulds are a species of coffer built up temporarily of wooden walls united 
by horizontal cross-pieces, which are secured by bolts. To the interior 
of these coffer walls may be affixed the moulds necessary to produce 
architectural forms, or the ornaments and decorations of staircases, 
portals, windows, &c, so that entire walls may be built in mass, with 
every appearance of being sculptured out of stone. For the prepara- 
tion of portable blocks, the moulds are more varied in construction. 
They take the form of every description of object of which stone is the 
usual material, and serve to produce vases, urns, busts, statues, or sim- 
ple cornices and friezes. 

The following proportions are given by Mr. Paul as those employed 
in the great monolithic structures of Paris, including the sewers and 
the substructures of the Exposition, viz : five parts of sand, one of lime, 
and one-quarter of one part of cement in bulk. Such is the rapidity 
with which constructions in this material are carried on, that in six or 
eight hours after beginning work on a given length of sewer, it becomes 
safe and practicable to remove and advance the centres ; and in four or 
five days after a section has been conrpleted, it may safely be turned over 
for use. 

For arches with a pitch of one in ten, the proportions are, for the sand 
and lime the same as given above, but the quantity of cement is doubled. 
The groined arches of the ventilators of the Exposition, and of the sub- 
structures of the gallery of refreshments surrounding the Exposition 
palace, were constructed to this pitch, and thus a floor of vast dimen- 
sions was supported by isolated columns one foot in diameter and dis- 
tant ten feet from each other in all directions. At the crown of the 
arches this floor was but a little more than five and a half inches thick. 
The span of the basement arches of the city barrack is nearly twice as 
great, being 18.3 feet, and these arches are built to the same pitch. At 
the crown, in this case, the thickness of the material is nine inches. One 
month after the completion of one of these it bore a weight of forty- 
eight thousand kilograms upon twelve square metres of surface, or of 
forty-eight tons upon a surface of ten feet by twelve. 

A church has been constructed at Vesinet of this material entirely, the 
whole being a mass of Mton without joints. The pit sand of the neigh- 
borhood was used, and the lime and cement were in the proportions first 
given above. But the pavements were made of a Mton richer in cement ; 
the quantity of this ingredient being made, for this part of the construc- 
tion, equal to that of lime. These pavements were very carefully rammed 
and smoothed with the trowel. In the lumber mill of Aubervilliers, 
the arches of the substructure, built of the Ooignet Mton, are twenty- 



302 PARIS UNIVERSAL EXPOSITION. 

eight feet in span and fourteen inches thick at the crown. All the 
machinery of the saws is firmly fastened to the floors formed by these 
arches, by means of cramp-irons secured with lead, without having 
occasioned any injury to the structure during all the time the mills have 
been in operation. 

The most important of the benefits which are to result from the use 
of the agglomerated betons is probably to be looked for in the superior 
stability and strength which they are destined to give to the foundations 
and basements of ordinary dwelling-houses. The usual mode of forming 
such constructions at present is to employ a certain amount of cut stone 
at intervals, and to fill up the intervening spaces with rubble masonry. 
The entirely dissimilar character of these two kinds of masonry, with the 
great number of bonds or surfaces of junction between them, produces 
unequal settling and the consequent cracking of the walls. Walls which 
are constructed of agglomerated beton are not liable to such accidents. 
Their whole mass forms but a single homogeneous block, stronger than 
even the rock on which it rests as a foundation. From the fact of their 
continuity, their weight is distributed over the entire area of the founda- 
tion, and no settling can take place so unequally as to produce fracture. 

In a dwelling of five stories, in Miroinesnil street, Paris, constructed 
of a single mass of beton, a staircase of the same material runs in heli- 
coidal form from the basement to the highest floor, moulded in the posi- 
tion where it stands. 

At the Exposition, there were presented specimens of the various ap- 
plications of this important material, including a pavilion, as illustrative 
of its adaptedness to building in mass, lintels, cornices, friezes, paving 
slabs, troughs, garden benches and tables, vases, monnments. urns, sta- 
tues, and nearly every other important object in which stone is commonly 
employed, whether for useful or for ornamental purposes. As scarcely ten 
years have passed since Mr. Coignet's first experiments were made, and 
as it is only within the last two or three that the process has been per- 
fected, or at least that its merits have been recognized, the beton agc/Jomere 
must be regarded as one of those new and useful things which the Ex- 
position of 1867 was first to bring conspicuously before the world. At 
the Exposition of 1862, the efforts which, up to that time, had been 
made in this direction, inspired in the jury in charge of the subject so 
little confidence that the report of that body disposed of them all in the 
following summary manner : " Many artificial stones which at first sight 
appear admirably adapted for this purpose [building] are found, when 
exposed to this unerring test, [actual experience of some years.] to be 
utterly wanting in durability. Xo artificial stone can. therefore, be con- 
sidered durable as compared with natural stone until it has undergone 
the test of long experience;" a test which the jury were not disposed to 
think had as yet been satisfactorily sustained by any such composition 
known to them. 

The crushing weight which the beton of Mr. Coignet is capable of 



ARTIFICIAL STONE — RANSOME's. 303 

resisting has been stated at four hundred kilograms per square centimetre, 
or nearly fifty-four hundred pounds to the square inch. Its resistance 
to a force of tension is thirty to forty kilograms the square centimetre, 
or four hundred to five hundred and forty pounds per square inch. 

RANSOME ARTIFICIAL STONE. 

More remarkable than the agglomerated betons, or than any other 
form of artificial building material yet invented, is the unique composi- 
tion of analogous character exhibited by Mr. Frederick Eansome, of 
London. This material is equally adapted to heavy constructions and 
to objects of art and ornament. Its strength is very extraordinary, 
greatly exceeding that of the sandstones and of most of the harder 
natural rocks in common use for architectural purposes, to some of 
which it nevertheless exhibits a striking resemblance in appearance. 
From the nature of the process of manufacture, it may be variously 
colored so as to represent the darker marbles ; or, in case white sand is 
selected as the basis, it may be made entirely colorless. Any kind of 
clean sand may be employed to form the bulk of the composition. The 
cement by which the particles are bound together, when the process of 
transformation is complete, is silicate of lime. A description of the 
interesting process, by the application of which, out of the most inco- 
herent materials, great masses of solid rock or ornamental objects of 
every variety of pattern are produced in the works of Mr. Eansome in 
the course of a few hours, was published during the continuance of the 
Exposition in Mr. Colburn's London journal Engineering, and this 
account so fully exhausts the subject, and is at the same time so lucid and 
satisfactory, that it is here substituted instead of the notice intended 
originally to occupy this place : 

" If Mr. Eansome has not found the philosopher's stone, he has at 
least produced a stone worthy a philosopher, and which promises to 
become the stone of the ages. For it appears to have elements of great 
durability, and it certainly possesses every other quality desirable in 
building stone, whether for structure or ornament. Although five years 
are not five centuries, chemistry has analyzed even the tooth of time, 
and can produce, within the period of a comparatively brief experiment, 
results identical with those of ages of atmospheric corrosion and disin- 
tegration. Mr. Kansonie's stone has been boiled, and roasted, and frozen, 
and pickled in acids, and fumigated with foul gases, with no more effect 
than if it had been a boulder of granite or a chip of the blarney stone. 
It has been boiled and then immediately placed on ice, so as to freeze 
whatever water might have been absorbed, and it has been also roasted 
to redness, and then plunged in ice water, but without any sign of crack- 
ing or softening, superficially or otherwise. Nor does its durability rest 
alone upon such evidence as this, for it is of the simplest chemical com- 
position ; and chemistry and geology alike testify to the durability, if 
not the indestructibility, of a stone which is nearly all silica, like flint, 



304 PARIS UNIVERSAL EXPOSITION. 

and onyx, and agate, and jasper. It has no oxidizable constituent; for 
silica, or silicic acid, is already oxidized, and thus it is unalterable in 
air : and as the new stone is almost impermeable, it Trill suffer little, if 
any, injury from moisture or frost. 

"And how marvellous, for its simplicity and beauty, is the process by 
which this stone is made ! Some toiling mason or other, hewing in the 
quarry or in the builder's yard, must have wished, before now, that 
stone, like iron, might be melted and run in moulds even though his own 
occupation were thus at an end. Did he ever, when by the sea-shore or 
by a sand-pit, think of cementing indissolubly together the countless 
millions of grains into solid rock % Mr. Eansome, no mason, however — 
unless he be, as he may be for anything we know, a member of the mys- 
tic brotherhood — did think of this. And he tried every cement he could 
lay his hands to, and did not succeed. The sand became little else than 
mortar by such sticking as he could effect. But he found out, at last — 
and we are speaking of a time more than twenty years ago — that the 
best sandstones were held together by silicate of lime. And so he set 
himself to work to produce this substance, indirectly, from flints, of 
which plenty could be found for the purpose. But the flints had to be 
liquefied first, and how could this be done ? Xot by heat, nor would 
caustic soda touch them, so the-chemist said. Flints might be boiled in 
a caustic solution for a week together, so long as the boiler was an open 
one, and lose very little by the operation. But by-and-by Frederick 
Bansome made one of the most unexpected discoveries in chemistry, viz., 
that when boiled in a caustic solution, under pressure, flints would melt 
almost like tallow before the fire. But we are not about to give the long 
history of the invention. With flint soup, or silicate of soda as a liquid, 
the question was what other liquid would, in mixing with it. turn both 
into an enduring solid ? What other liquid would turn both into silicate 
of lime, the substance he was seeking ? When he found that chloride 
of calcium (in solution) would, when mixed with silicate of soda, turn 
both into flint, or something very much like it, the road was clear, and 
the manufacture of stone from sand was as simple and as beautiful a 
process as the making of Bessemer steel from pig-iron by blowing air 
through it when in the melted state. 

" During the month of June, 1867, on the occasion of a visit of a party 
of about one hundred and eighty gentlemen, comprising heads of pub- 
lic offices and boards, chemists, geologists, engineers, architects, and 
others, to the new works of the Patent Concrete Stone Company, at East 
Greenwich, Mr. Bansome showed and explained the whole process of 
making stone from sand, and exhibited some hundreds of the objects 
and ornaments, many of them of great beauty, already made to the 
order of architects and builders for various new buildings in England 
and abroad. 

'•The sand, a clean-grained, slightly brownish sort, just such as a dis- 
honest grocer might select for increasing the gravity, specific or otherwise. 



ARTIFICIAL STONE. 305 

of his sugar, comes from near Maidstone. There is no end to the quantity 
of it, and we believe it costs less than three shillings a ton in the Thames. 
There are flints enough for a hundred years to come brought up from 
the chalk pits at Charlton ; and the caustic soda and the chloride of cal- 
cium, the latter a waste product of the soda manufacture, are bought 
of the wholesale chemists. The silicate of soda is made from the flints 
and caustic soda as follows : The flints are heaped upon iron gratings 
within a series of cylindrical digesters, of the material, size, and form 
of small steam-boilers. A solution of caustic soda is then added ; the 
digester is then closed steam-tight, and the contents are boiled by steam 
of seventy pounds taken from a neighboring boiler and led through the 
solution in a coil of iron pipes. The solution of caustic soda is prepared 
of a specific gravity of about 1.200. The flints are dissolved into l solu- 
ble glass,' and are drawn off in that state as a clear though imperfectly 
liquid substance, which is afterwards evaporated to a treacly consistency 
and color, and of a specific gravity of 1.700. 

"The sand is completely dried, at the rate of two tons an hour, within 
a revolving cylinder, through which hot air is forced by a centrifugal 
fan. A small portion of finely ground carbonate of lime, say Kentish 
rag, or even chalk, is mixed with the sand, the more closely to fill the 
interstices ; and each bushel of the mixture is then worked up in a loam 
mill along with a gallon of the silicate of soda. Thoroughly mixed with 
this substance, the sand has a sticky coherence, sufficient to enable it to 
be moulded to any form, and, when well rammed, to retain its shape, if 
very carefully handled. In this condition — moulded, of course, and any- 
thing that can be done in founder's loam maybe done in this sand, sticky 
with silicate of soda — in this condition it is ready for the solution of 
chloride of calcium. The instant this is poured upon the moulded sand, 
induration commences. In a minute or so little lumps of sand, so slightly 
stuck together by the silicate of soda that they could hardly be kept 
from falling to pieces within the fingers, were solidified into pebbles so 
hard that they might be thrown against a wall without breaking, and only 
a short further saturation was necessary to indurate them throughout. 
In other words, on the instant of contact, the silicate of soda and the 
chloride of calcium mutually decompose each other and reunite as sili- 
cate of lime and chloride of sodium, the former practically indestructi- 
ble in air, the latter, common salt, perfectly deliquescent and removable 
by washing, although the stone, after the washing, is impermeable to 
water. Plaster of Paris does not set quicker than silicate of soda and 
chloride of calcium. 

" The chloric solution is first ladled upon the moulded sand, and, the 
hardening going on, the objects are afterwards immersed in the solution 
itself, wherein large pieces are left for several hours, the solution being 
boiled in open tanks by steam led through it in pipes. This expels any 
air which may have lodged in the stone, and possibly heightens the 
energy of union with the silicate. 
20 I A 



306 PARIS UNIVERSAL EXPOSITION. 

" After this the stone is placed, for a longer or shorter time, according 
to the size of the object, under a shower bath of cold water. This is 
not, by bathing, to convert it into Bath stone, although were the Bath 
stone a sand stone instead of an oolitic formation, this name would do 
as well as any. The salt, or chloride of sodium, deposited throughout 
the interstices, is sought out and washed away, in brine, by the water, 
and were it not that a portion of undecomposed chloride of calcium is 
also washed out, this brine might be profitably evaporated for common 
salt. Xow this searching out of the salt by the water would appear to 
prove that the stone was perfectly permeable, but, by one of those para- 
doxes with which chemistry abounds, the stone, when once freed from 
salt, is almost impermeable. The action is one which, if it can be ex- 
plained at all, cau only be explained as one of the phenomena of dialysis, 
as experimentally investigated by Professor Graham. There is no doubt 
whatever that salt has been deposited everywhere throughout the stone, 
no doubt that it is afterwards completely washed out, and yet the stone 
as effectually resists the passage of water afterwards as if it were granite 
or marble. 

"It is not necessary to describe the variety of objects that may be 
made in the new stone. It is practically a fictile manufacture, although 
not indurated by fire, and, unlike fictile goods, having no shrinkage 
or alteration of color in the making. Whatever the required size of 
the finished stone, it is moulded exactly to that size, with no allowance 
as in moulding fire-clay goods or in pattern-making for castings in 
iron. The heaviest blocks for works of stability, and the most elabo- 
rately ornamental capitals, tracery, or copies of statuary may be made 
with almost equal facility. For any purpose for which natural stone 
has ever been used for construction or architectural ornament, the 
artificial stone will fitly take its place. Mr. Fowler has used it exten- 
sively in the stations of the Metropolitan railway : Messrs. Lucas 
Brothers have used it with success in various works ; several lnanuiac- 
turers at Ipswich and elsewhere have the bed-stones of their steam- 
engines, steam hammers, oil mills, &c, formed of the new stone. Mr. Ban- 
some has moulded a large number of Ionic capitals for the Xew Zealand 
post ofiice, and still more richly embellished capitals, modelled from those 
of the Erectheum at Athens, for public buildings at Calcutta, besides a 
great amount of decorative work for English architects. We understand 
that some thousands of Corinthian capitals of this stone are specified for 
the new St. Thomas's Hospital, and the architects of the Grand Hotel of 
New York have decided to employ it for all the decorative work of the 
grand court of that edifice. 1 

"While, however, the new stone affords every facility for ornamental 

moulding, we consider that its more important purpose is as a substitute 

for ordinary cut building stone, and for that employed in pilasters, win- 

1 This project has been abandoned, but the fact mentioned shows that the invention of 

Mr. Ransome is appreciated so far as it has become known in our country. 



APPLICATIONS OF ARTIFICIAL STONE GRINDSTONES. 307 

clow dressings, garden balustrades, &c. It is truly the stone for the mil- 
lion, as well as for the inullion, and ought to take the place of stucco 
for exterior work in our town houses. We have not heard that the 
workmen have set their faces against it, although an intimation of this 
sort would not surprise us, but we should suppose that a proper knowl- 
edge of its advantages would insure its general adoption in spite of any 
possible opposition of this kind. We believe it to be the fact that 
builders are slow to move, but there are always exceptions, and, as in 
other trades, great improvements like this will make way against all 
opposition. 

" On the visit to the new works above spoken of, Mr. Dimes made an 
experiment upon two cubes of the new stone, each four inches square, 
and made only ten days before. One took forty-four and the other forty- 
eight tons to crush it, while a like cube of Bath stone gave way at four- 
teen tons. Mr. John Grant, the assistant engineer to Mr. Bazalgette, of 
the Metropolitan Board of Works, also made experiments on the same 
occasion, on the tensile strength of the stone. Specimens having a sec- 
tional area of two and a quarter inches bore, respectively, eight hundred 
and seventy pounds and twelve hundred pounds. These specimens had 
been made but five days previously. 

u The new works of the Patent Concrete Stone Company have been laid 
out upon a large scale and admit of easy extension. They are already 
engaged upon a large amount and a remarkable variety of work, and it 
cannot be doubted that the excellence and great cheapness of their man- 
ufacture, the former now proved by nearly every test known to engi- 
neers, architects, chemists, and builders, will rapidly secure for it a vastly 
wider introduction than it has yet attained." 

Besides the important applications of the Bansome process to the 
manufacture of building stone, and to the reproduction of the works of art, 
it has furnished a very valuable aid to mechanical industry, by providing 
the best material yet known for the manufacture of grindstones. The 
extreme hardness of the silicious cement which binds together the grains 
which compose this material, secures it from the rapid disintegration 
which takes place when steel tools are ground on the best grindstones 
formed from natural rock. The following interesting notice of these 
stones is derived from the same source to which we are indebted for the 
foregoing description : 

"The success which has attended the application of Mr. Ransoine's 
beautiful process to the manufacture of artificial grindstones has been 
so marked that there seems little doubt that the use of natural stones 
for grinding purposes will eventually become the exception instead ot 
the rule. Amongst other firms, Messrs. Bryan Donkin & Co., the well- 
known engineers of Bermondsey, have tried experiments which very 
decisively prove the advantages of the artificial over the natural stones. 
Messrs. Donkin were first supplied with a pair of Mr. Ra-nsome's arti- 
ficial grindstones in December last, and early in the present year they 



308 PARIS UNIVERSAL EXPOSITION. 

carefully tested these stones and compared their efficiency with some 
Newcastle stones at their works. Both the natural and artificial stones 
were mounted in pairs on Muir's plan — a system in which the peripheries 
of the two stones of each pair rub slightly against each other, with a 
view of causing them to maintain an even surface — and the two sets of 
stones were tried under precisely the same circumstances, except that 
the Newcastle stones had a surface speed more than twenty per cent, 
greater than that of the others. 

"The trials were made as follows: A bar of steel, three-fourths of an 
inch in diameter, was placed in an iron tube containing a spiral spring, 
and the combination was then arranged so that the end of the bar pro- 
jecting from the one end of the tube barely touched one of the artificial 
stones, while the other end of the tube rested against a block of wood 
fixed to the grindstone frame. A piece of wood of known thickness was 
then introduced between the end of the tube and the fixed block, and 
the spiral spring, being thus compressed, forced the piece of steel against 
the grindstone. The same bar of steel was afterwards applied in the 
same way, and under precisely the same pressure, to the Newcastle 
stone, and the times occupied in both cases in grinding away a certain 
weight of steel from the bar were accurately noted. 

" The results were that a quarter of an ounce of steel was ground from 
the bar by the artificial grindstone in sixteen minutes, while to remove 
the same quantity by the Newcastle stone occupied eleven hours; and 
this notwithstanding that the surface speed of the latter was, as we have 
stated, more than twenty per cent, greater. Taking the twenty per cent, 
greater speed of the Newcastle stone into account, it will be seen that 
the eleven hours run by it were equal to thirteen and three-quarters hours 
at the same speed as the artificial stone, aud the proportioual times occu- 
pied by the two stones were thus as sixteen minutes to thirteen and 
three-quarters hours, or as one to fifty-two, nearly ! 

" Such a result as this is something more than remarkable, and it is 
one which would scarcely have been credited, even by those who made 
the experiments, if it had not been fully corroborated by subsequent 
experience in the working of the artificial grindstones. Since the experi- 
ments above described were tried, Messrs. Donkin have set another pair 
of the artificial stones to work, and these, which are now in regular use. 
have given even more satisfaction than those first tried. The saving in 
time, and consequently in labor, effected by the use of the artificial 
grindstones, is, in fact, so great, that Messrs. Donkin have determined 
to use these stones exclusively in future; and we may add that the 
artificial stones are so much preferred by the workmen, that those men. 
even, who are employed in shops at some distance from that in which 
the stones at present in use are situated, prefer taking the trouble to go 
to them to using the Newcastle stones in their own shops. In addition 
to their great efficiency the artificial grindstones possess the advantages 
of being able to be manufactured of any size, and of any degree of coarse- 



ARTIFICIAL FUEL COMPRESSED COAL. 309 

ness of grain, and they can thus be specially adapted to any particular 
class of work, while the process of their manufacture insures their 
being of uniform texture throughout, and free from the flaws and hard 
and soft places found in natural stones. Altogether, we believe that the 
general adoption of the artificial grindstones is merely a matter of time." 

III.— AETIFICIAL FUEL. 

AGGLOMERATED COAL. 

By this term is meant the solidification of the waste of coal, the dust 
and minute fragments of which no use could be made, into masses capa- 
ble of being handled, and which, in this form, become as valuable a 
combustible for every purpose as natural coal itself. Some qualities, 
indeed, of this artificial combustible, appear to give better results than 
the best coals with which they have been compared. This form of fuel 
was among the most interesting of the economical novelties which pre- 
sented themselves in the Exposition. The machines used in the manu- 
facture were also exhibited by several of those who presented their 
products. Among these there was considerable variety, but all of them 
appeared to be very well designed. A subject of such interest early 
occupied the attention of the writer; but while he was still engaged in 
the collection of information in regard to it, an article so full and satis- 
factory was published in the London Engineering, that it has seemed 
to be preferable to quote it entire rather than to present an original 
account. The writer says : 

" Artificial fuels may be said to now appear for the first time in an 
international exhibition as a practical and accomplished fact. We have 
compressed coal slack and coal dust, forming a solid and easily trans- 
portable fuel, of excellent quality, produced by a simple and inexpensive 
process from the smallest particles of coal which have generally been 
considered as utterly valueless, and have formed an encumbrance rather 
than a source of gain to the proprietors of coal mines. This process, 
first long ago adopted with considerable success in England, was taken 
up in Belgium about five years ago, and has since then been introduced 
into France and Austria with perfect success. The Paris Exhibition 
represents this new branch of industry in its present state by samples 
of artificial fuel, and by models and illustrations of the different machines 
employed in their production. 

"The process of compressing coal dust consists in mixing this material 
with a cementing matter, which, after being exposed to a high pressure, 
will effectively bind the loose particles of coal together, and form a solid 
block of considerable strength. With some kinds of bituminous coal it 
has been found that the mere application of considerable pressure at a 
somewhat elevated temperature is sufficient for making the small particles 
adhere to each other, so as to prevent them from falling into dust upon 
the fire- grate, and to make them burn like solid blocks of coal or of wood. 



310 PARIS UNIVERSAL EXPOSITION. 

The fuel compressed in this manner is, however, rarely capable of stand- 
ing the rough usage of transportation, and it is, therefore, only in special 
localities that it can be applied, while those kinds of artificial fuel which 
are now an article of commerce on the continent are made by the appli- 
cation of a cement. The first cement ever applied, we believe, was clay ; 
but this material being incombustible, and producing a very large quantity 
of ashes in burning, was soon discarded. The application of coal tar was 
then resorted to, and gave very good results. The different kinds of coal 
required more or less of the cementing material according to their own 
more or less bituminous character, and according to the higher or lower 
pressure to which they are exposed. Coal tar, as a cement, has, how- 
ever, in the most recent practice been superseded by another organic 
substance obtained as a residue in the manufacture of starch, and practi- 
cally almost valueless for other purposes. This substance can be employed 
in quantities not exceeding one per cent, of that of the coal dust to be 
compressed with it : it leaves no ashes in burning, and, what is still more 
importaut as compared with the ready liquidity of coal tar, it does not 
melt at a high temperature, so that its binding effect is not lessened when 
exposed to the heat of the fire. The Paris Exhibition contains compressed 
fuel from several French collieries, among which the Mines de Grande 
Combe, the €ompagnie Anonyme des Houilleres de la Chazotte, near St. 
Etienne, and Mr. Felix Dehaynin, of Paris, are the most important, the 
latter exhibitor having one of his establishments in Marcinelle, in Belgium. 
From Austria the Xorthern Railway Company, who own extensive coal 
pits at Ostran, in Moravia, have also sent some very good samples of 
their artificial fuel. The compressing machines are of very different 
construction, but that most approved of seems to be the machine invented 
by Mr. Evrard, the engineer of the company of Chazotte, and another 
constructed by Mr. Mazeline. The material in this machine is forced 
within cylindrical pipes of cast iron by the resistance offered to its passage 
through the pipe, and caused by the friction of the material against the 
sides of the pipe. The compressed fuel passes out of these cast-iron pipes, 
as a continuous cylindrical bar, which is broken in suitable lengths, and 
then sold much in the form of round logs of wood. Mr. Mazeline's machine, 
exhibited both in original and in a model, produces bricks of prismatic 
form. It consists of a mixing apparatus, which feeds the material into 
a kind of brick-making machine, having about twelve square moulds 
arranged in a circular frame, which has a rotating movement. Each die 
is worked by a square piston projecting into it from the bottom, and 
acted upon by an inclined plane which presses the pistons upward during 
the revolution of the circular frame, so that each brick is completed and 
delivered by the respective mould, making one complete turn round the 
central axis of the machine. These bricks have the advantage of being- 
more easily stored than those of cylindrical form, but the machines 
do not produce the same quantity as those of equal cost on Mr. Evrard's 
plan. The character and qualities of these kinds of compressed fuel which 



AGGLOMERATED COAL 311 

on the continent have the name of briquettes or charbon agglomere, (coal 
bricks,) must, of course, depend upon the nature of the original coal 
from which they are produced. The Belgian coal, and that of St. Etienne, 
which always requires washing, on account of the pyrites and other im- 
purities which it contains, must go through this process before being 
compressed ; the coal from screenings and dnst, from Ostrau, on the other 
hand, is so pure as to require only cementing together to make an ex- 
cellent fuel. Mr. Dehaynin states that his machine, being a modification 
of Mr. Evrard's construction, produces ten tons of fuel per hour, with a 
motive power of eighty horses. The whole machine weighs about sixty- 
five tons, with all its accessories and gearing, including the steam-engine. 
The coal bricks are slightly heavier than natural coal, and their calorific 
effect has been found fully equal, and, in some cases, even superior, to the 
latter. The process of washing removes about five per cent, of the weight 
of the coal dust, representing incombustible impurities, and the compressed 
fuel leaves only six to seven per cent, of ashes. Mr. Dehaynin's works pro- 
duced one hundred and seventy-five thousand tons of this fuel last year, 
which has beeu sold to the different railway companies and the navy, 
besides a great quantity for household purposes, for all of which appli- 
cations the briquettes are preferable to natural coal on account of its 
greater regularity of form, greater cohesion, and consequently improved 
cleanliness in firing, besides also for its high heating effect. The com- 
pressed fuel of Chazotte leaves only four or five per cent, of ashes. It 
is made from anthracite coal, containing eighty-one per cent, of uncombined 
carbon, 16.5 per cent, of hydrocarbon, and 2.5 per cent, of ashes. Some 
experiments made by the Messageries Imperiales, and by other parties, 
have shown a superiority of this fuel over the best coal from Cardiff, 
amounting to ten per cent., weight for weight. The Northern Railway of 
Austria has a production of fifteen thousand tons per annum. The bri- 
quettes evaporate 7.1 to 7.2 pounds of water per pound of fuel in regular 
practice with locomotives for passenger trains, which use this fuel in 
preference to coal. The large coal from the same mines has about the 
same heating effect, while the coal slack in its natural state could not 
be considered to have more than five-eighths of this heating effect, even 
with careful firing and a suitable grate. The coal bricks of the Northern 
Railway are prismatic, nine inches long, five inches wide, and four and a 
quarter inches thick ; they weigh eight pounds each, and are made with a 
cement consistin g of the refuse of the starch works. They are compressed 
in a damp state, and afterwards dried in a kiln heated overhead by a 
current of hot air. The time for drying is about three hours. The form 
of these bricks makes them extremely convenient for all practical opera- 
tions. Their weight being always constant, it requires only to count the 
number of bricks for delivering the exact quantity of fuel required, except, 
of course, to purchasers. The stowage is very much facilitated, and, the 
loss from coal crumbling into dust is considerably lessened. The prime 
cost of this material, taking the coal dust at its selling price at the pit's 



312 PARIS UNIVERSAL EXPOSITION. 

mouth, is considerably below that of the solid coal drawn from the same 
pits, while it is in many instances effective in lessening the working ex- 
penses of mining operations, thereby reducing the prime cost of the coal 
itself. There can be no doubt that this valuable process will soon find 
its way into the collieries of England, where its beneficial effects will be 
incalculable. Considering the enormous quantities of material, now next 
to valueless for all purposes of industry, which may be converted into 
the most excellent fuel by such simple means, and at a moderate cost, 
the process of compressing fuel appears to be one of the most important of 
modern inventions, and one of the greatest steps in advance represented 
by the present Exhibition. It is a practical and commercial reality, but 
still in the first stages of its infancy. Its introduction into the English 
coal districts can hardly be postponed any longer, and, if once in opera- 
tion on that enormous scale which it is capable of acquiring in the British 
collieries, will form one of the greatest sources of wealth ever known any- 
where." 

Important as the introduction of this manufacture into the coal regions 
of England may be to that country, it can hardly be less so to the United 
States. To save the immense waste which is continually going on wherever 
coal is handled, whether at the mines, or in transportation, or in the hands 
of the venders on the large scale, would not only have the effect mate- 
rially to add to the comfort of multitudes who now suffer from the high 
prices of fuel, but would also powerfully contribute to the economy of 
every industry. 

IY._MATEEIAL AND MANUFACTURE OF PAPER. 

VARIETY OF SPECIMENS A^'D MATERIAL. 

The variety of the specimens of manufactured paper exhibited was 
almost endless, and the beauty of the superior qualities presented by 
nearly every country of Europe, but especially by France, England. 
Austria and Prussia, was all that could be desired. In regard to pro- 
cesses of manufacture, nothing was presented of especial novelty. Bel- 
gium only exhibited a machine for the continuous manufacture, which. 
however, was not put into operation. It was exposed by Messrs. Dau- 
trebande & Thiry, of Huy, and as a specimen of superior workmanship 
was eminently creditable to its constructors. 

What was chiefly interesting in connection with this important indus- 
try was the display of papers manufactured more or less entirely of 
materials other than cotton or linen rags. The immensely increased 
consumption of paper of all descriptions in recent years, and the steadily 
increasing demand, a necessary consequence of the progress of enlighten- 
ment, the growth of commerce, the improvement of the arts, and the 
enlargement of the operations of industry in all its departments through- 
out the world, have rendered it a matter of the greatest urgency to 
provide some new and inexpensive means of maintaining the supply. 



MATERIAL AND MANUFACTURE OF PAPER. 313 

Cellulose, the essential constituent of paper, is found in sufficient abun- 
dance throughout the vegetable kingdom; but the number of plants 
from which it can be separated in condition suitable to be manufactured 
into paper is comparatively small. In order to fulfil this purpose, it 
must be capable of forming strongly coherent films, by the interlacing 
and felting together of the fibres of which it is composed. These fibres 
must, therefore, have a certain length, and the processes by which they 
are separated from the substances with which they are found naturally 
associated, and which impair their usefulness for this manufacture, must 
not be such as to injure their tenacity. In certain plants, the fibres of 
the cellulose are conspicuous and separable without much difficulty. 
The various descriptions of cotton furnish it almost pure, or contami- 
nated only by a little oil. In flax and hemp it is encrusted with other 
substances, organic and mineral, more or less difficult to be disposed of, 
but which when removed leave it in long and tenacious bundles of 
fibres. In jute, China-grass, the American aloe, straw, spartero, and the 
grasses generally, it is found similarly combined and is separated still 
less easily. It forms a large portion of the solid mass of all descriptions 
of wood, from which it may be obtained by processes either mechanical 
or chemical, or by both combined ; but it is generally then too short in 
fibre to be available in the manufacture of paper without an admixture 
of a large proportion of cotton or linen rags. Several of the softer 
woods have, however, been largely employed in the preparation of paper 
pulp, among which may be mentioned poplar, elm, fir, beech, linden, and 
birch. The most beautiful papers exhibited were from Japan, and were 
manufactured from the bark of the so called paper tree, the Broussonetia 
papyri/era. 

WOOD PULP — VOELTER'S MACHINE. 

Wood pulp has been very largely introduced into the paper manufacture, 
both in Europe and in our own country, and it is prepared at present 
on a large scale by both the processes above mentioned. There are now 
in Germany more than thirty establishments engaged in its preparation 
by the mechanical method, in all of which a machine is used which was 
patented some years ago by Henry Yoelter, of Wurtemberg. One of 
these machines, exhibited by Messrs. Decker, Brothers & Co., of Can- 
statt, was in constant operation during the Exposition, in the Wurtem- 
berg annex. 

This machine, which is of very large dimensions, presents the appear- 
ance of a succession of tanks at different levels, like a flight of steps. 
At the summit is what is called the dejihrer, a kind of rasping mill, in 
which the fibres of the wood are torn off and separated by the action of 
a coarse cylindrical stone against which it is pressed, and which is kept 
in constant revolution. In the machine exhibited, this stone had a 
diameter of about four feet and a thickness of sixteen inches, and it re- 
volved one hundred and fifty times per minute. This is nearly the largest 



31 -4 PAEIS UNIVERSAL EXPOSITION. 

model constructed, though there are several smaller. It is capable of 
producing daily (running twenty-four hours) about half a ton of wood 
pulp " air-dry ; " by which, however, it is to be understood that the 
substance still contains about fifty per cent, of water, which is necessary 
to preserve it in good condition during transportation. A force of five 
horse-power per hundred weight per day is expended in driving the 
machine. The amount of pulp delivered is equal in weight to half the 
raw material consumed. Two or three attendants only being necessary, 
it is easy to make an estimate of the probable expense of running such 
a machine in a given locality. 

The wood is prepared for the machine, by being sawed into lengths 
of fifteen or sixteen inches, after having been first deprived of its bark 
and reduced to the diameter of about five or six inches. In case there 
are knots, these are removed by boring. If they cannot be se removed 
the wood is rejected. Each billet is then placed in a holder adapted to 
apply it firmly to the stone. Six such holders were attached to the 
machine exhibited, and were all in use at once, occupying about one 
quarter of a circumference. The pressure is applied by means of a 
screw behind each holder, which is very gradually driven by the machine 
itself. A single band acts at once upon all these screws by intermediate 
mechanism, and in case the several billets are not ground off with equal 
rapidity, the proper adjustment effects itself by the slipping of the band. 

The stone is enclosed in an iron box, and water flowing in constantly at 
the top removes the disintegrated fibres, as fast as they are produced. 
From the mill the comminuted mass is carried along, in suspension in 
water, into the first tank, in which there is a cylindrical strainer, formed 
of very coarse wire gauze, constantly in revolution. The discharge 
from this tank, which, to prevent overflow, must be equal to the supply, 
takes place from the axis of this strainer, which is made large and tubu- 
lar for the purpose. The flow is. therefore, from the exterior to the inte- 
rior, through the meshes of the strainer, and the slivers and coarser 
fragments of the wood, being thus prevented from passing, are from time 
to time removed. The water, with the available portion of the fibre, is 
discharged through a lateral duct into a second tank at a lower level, 
where it undergoes a straining similar to the preceding, but through a 
gauze considerably finer. The process is repeated until the pulp has 
undergone four successive strainings, when the material is passed into 
a fifth tank in which the strainer is so fine as to allow the water only 
to pass. Between the second and third of these straining tanks, there 
is an auxiliary apparatus which must not be overlooked. It is called a 
refiner, and resembles an ordinary grist-mill. Into this are conveyed 
the coarser fragments detained by the second drum, and these here 
undergo a second grinding. The three cylinder strainers below the 
refiner constitute what is called the sorting apparatus, aud furnish pulp 
of successive degrees of fineness. The manufacturers state that they 
have furnished, up to 867, ninety of these machines to different coun- 
tries, one of which was sent to America, (Canada. 



MATERIAL AND MANUFACTURE OF PAPER. 315 
WOODS BEST ADAPTED TO THE PRODUCTION OF PULP. 

Tlie woods wliich furnish the best fibre, that is, the fibre of greatest 
felting power, are pine and fir j but the poplar and linden furnish the 
whitest pulp. The fibre of the birch and beach is shorter than that of 
either of the foregoing, but is much in nse in Belgium and France. No 
wood pulp yet ma ufactured, however, will suffice to prepare a paper of 
good quality by itself. Its fibres are in all cases excessively short when 
compared with those of linen or cotton rags. If a good piece of cotton 
paper be softened in water and carefully pulled to pieces by means of 
needle points, its separate fibres maybe distinguished by the naked eye, 
and will be found sometimes to exceed a tenth of an inch in length. 
Those of wood pulp are nearly undistinguishable without a magnifier, 
and will not average a fifth part of the same length. A certain propor- 
tion of this material may, however, be employed, without very sensibly 
diminishing the durability, which is so important a property of paper ; 
but this proportion can hardly exceed one-fifth part. For papers of 
secondary quality, as for newspapers, posters, wall paper, &c, fifty per 
cent, is sometimes employed, though not with advantage, as is evident 
in the examples furnished in some of our daily journals. In the rougher 
wrapping paper a still larger proportion is introduced, the material being 
also of a coarser character. 

CHEMICAL TREATMENT OF MATERIALS FOR PAPER. 

It is, however, by chemical processes, or by processes mainly chemical, 
that substitutes for rags in the manufacture of paper are at present 
principally prepared ; and though wood is the material employed in some 
of these processes, they embrace also straw, grasses, and other vegeta- 
ble substances. One of these processes consists in subjecting the sub- 
stances operated on, after they have been reduced to proper dimensions, 
to the action of strong solutions of the fixed alkalies, under pressure and 
at high temperatures, (300° F,) and subsequently bleaching by chloride of 
lime. After the operation, the alkali (potash or soda) may be recovered 
with little loss. 

Another mode of treatment is to subject the material first to the action 
of strong hydrochloric acid, to which has been added a small quantity of 
nitric, continuing the immersion for a number of hours. Or the effect 
desired may be obtained by means of a very dilute solution of the same 
acids, provided the temperature be elevated to boiling. The substance, 
after this digestion, is washed and drained, and finally ground to a pulp. 
It is then digested in a solution of ammonia, and afterwards bleached by 
means of chloride of lime. Numerous establishments in France and 
other countries of Europe prepare paper pulp by these processes, to the 
extent of from one to ten tons a day. The superiority of the pulp thus 
prepared over that prepared by mechauical means is very considerable, 
and results from the fact that the fibre is less broken, and is probably 



316 PARIS UNIVERSAL EXPOSITION. 

much more thoroughly freed from the indurating substances which 
diminish its flexibility and increase its brittleness. The chemically pre- 
pared pulp can be used to the extent of four-fifths, while that prepared 
mechanically can at best be used in no greater proportion than thirty 
per cent., unless for papers of avowedly inferior quality. 

BACHET AXD MACHARD'S PROCESS. 

To the chemical processes above mentioned may be added another' 
invented by Messrs. Bachet and Machard, and described by Mr. Payen, 
in his jury report, which proposes to convert a part of the substances 
incrusting the fibres of wood first into grape sugar, and then into alco- 
hol, while transforming the fibre itself, at the same time, into a pulp 
suitable for the manufacture of paper. The process, on a large scale, is 
conducted as follows: Into a large vessel, containing more than two 
thousand gallons of water and one thousand six hundred pounds of 
hydrochloric acid, there are introduced two tons of fir wood in the form 
of billets. By means of a current of steam the water is maintained in 
ebullition for twelve hours, after which the acid solution is withdrawn 
and nearly saturated with carbonate of lime. Yeast is added, and the 
temperature maintained at 75° to 80° F. Subsequent distillation yields 
a considerable quantity of alcohol. The wood is then crushed after wash- 
ing, and the coarser parts are separated by levigation. A brown pulp 
is left which is very suitable for heavy wrapping paper. A lighter 
paper of similar kind is obtained by compressing the brown paste with 
rollers, and rolling the boards thus produced around mandrels, which 
are placed upright in a tight vessel to which chlorine gas is supplied. 
The boards being still charged with six per cent, of water, absorb 
more than a cubic foot of gas to the pound of the solid, supposed dry. 
The color is then found to have passed from a brown to a reddish tint, 
and the paper formed of the pulp in this condition is very handsome. 
In order to obtain a perfect white, the pulp, in the condition to which 
it is brought by the process just described, is first digested three sev- 
eral times in lime water, and then treated with ten per cent, of carbo- 
nate of soda at a temperature near the boiling point. It is then very 
thoroughly washed and afterward subjected to the action of chloride 
of lime. 

The wood, as reduced to billets before the chemical operation com- 
mences, is in weight about four-fifths of the original raw material. The 
weight of the brown or red pulp obtained in the first process is about 
one-fourth that of the prepared wood; and in the final purification, for 
the purpose of obtaining a fine white paste, there is a loss of thirty 
per cent. The total product of paper of this quality is, therefore, about 
one-sixth part of the prepared wood, or one-seventh of the raw material 
in weight. The net cost is a little over fifty francs the hundred kilo- 
grams, or one hundred dollars a ton. In general, it is stated by Air. 
Payen that the chemically prepared pulps cost less than pulp from rags 



EXTRACTION OF OILS. 317 

by one-half. At present, according to the same authority, the annual 
production of the material of paper directly from various vegetable 
sources, amounts to one-tenth of the whole consumption. This frac- 
tion is doubtless destined to be rapidly increased. 

Y.— EXTRACTION OF OILS BY MEANS OF SULPHIDE OF 

CAEBON. 

EXHIBITION BY SCHLINCK AND RUTSCH. 

An important and interesting industry, which has sprung up within 
a comparatively recent period, was illustrated at the Exposition in a 
collection exhibited by Messrs. Schlinck and Putsch, of Ludwigshafen, 
Bavaria, of a variety of vegetable oils separated from oleaginous seeds 
and nuts without pressure, by solution in the bisulphide of carbon. In 
this process the seeds are in the first instance crushed, ground, or other- 
wise reduced to a fragmentary or pasty condition. They are then im- 
mersed in the solvent, which thoroughly extracts the oil and resin which 
they contain, but leaves the substance otherwise unaltered. The vola- 
tility of the sulphide is so great that it is easily distilled off without 
loss, leaving the oil, like the raw oils extracted by pressure, contami- 
nated to some degree with resinous and coloring matters, which are 
removed by a second process of refining. 

REMOVAL OP OIL FROM WOOL. 

This method of separating oils, fats, and resins from the solid sub- 
stances with which they are mechanically combined, has been hereto- 
fore in use for the purpose of removing the animal oil from wool, and 
also for the purpose of cleansing and restoring to use those portions of 
fleeces which have been made unavailable by marking the sheep with 
tar or other resinous material. It has been employed before for the 
same purposes to which the exhibitors above named have applied it, 
but hitherto only as supplementing the mechanical process of separat- 
ing oil from seeds or olives by operating on the solidified residua which 
are known under the name of oil-cake, marc, &c. At the International 
Exposition of 1862, Mr. E. Deiss, of Paris, exhibited specimens of supe- 
rior oils extracted in this manner from the marc of olives. Mr. Payen, 
in his report on that Exposition, has described the process as originally 
applied successfully to the cleansing of wool by Mr. Moison, of Mouy, 
Department of the Oise in France ; and as this process illustrates the 
principle of the operation in other cases, though the details may be dif- 
fereut, it is here given in abridged form from that report. 

It is to be observed in the first place that the case of wool presents a 
difficulty which is not encountered when the object in view is only to 
obtain the oil which the substance operated on happens to contain. 

The avooI itself is in this case the important material, and the value 
of the oil separated from it is a trifle of secondary consequence. In the 



318 



PARIS UNIVERSAL EXPOSITION. 



original experiments the point of difficulty in the practical problem was 
found to be how to expel the bisulphide from the wool after the opera- 
tion of solution had been completed, without injury to the wool itself. 
Too great heat, in whatever manner applied, was found to have the 
effect of hardening the fibres, making them cohere, and giving them a 
tinge of a yellowish brown color, which was variable in intensity accord- 
ing as the material had been a longer or shorter time in contact with 
the fatty matters removed. The mere volatilization of the bisulphide 
was effected without difficulty. It sufficed for this to introduce into the 
vessel containing the material to be operated on, either boiling water or 
steam ; but the injurious effects above described invariably followed. 
Mr. Moison discovered at length that with proper arrangements a cur- 
rent of air heated to a temperature considerably below that of boiling 
water, 70° or 80° C=160° to 175° F., would remove the liquid entirely, 
and leave the fibre of the wool wholly uninjured. The apparatus em- 
ployed in conducting this process is shown in the Fig. 80 annexed. The 
wool to be subjected to the operation is introduced into a cast-iron 




Moison's apparatus for removing oil from wool. 

cylinder, A, surroundedby a jacket into which steam maybe conducted 
when it is necessary to raise the temperature. One hundred kilograms, 
say two hundred and fourteen pounds, of wool are placed in this 
cylinder at once. There is within the cylinder a false bottom perforated 
with numerous holes, with a small free space beneath it. Upon the top 
of the wool is placed a circular follower or compresser. fitting the inte- 
rior of the cylinder, and perforated also with holes like the false bottom. 
Three rods connected with this follower pass through stuffing boxes in 
the lid, and may be driven downward by means of fixed screw-nuts, the 
rods having screw-threads cut upon their prolongations above the cylin- 
der. The object of this arrangement is to compress the wool to a cer 



REMOVAL OF OIL FROM WOOL. 319 

tain extent, since the success of the operation is always most satisfactory 
when the mass of the material is reduced in advance to about one-half 
its original volume. 

The lid is secured air-tight by means of bolts and screws, a leaden 
washer being introduced into the i( oint. Matters being thus prepared, 
liquid bisulphide of carbon is thrown into the cylinder beneath the false 
bottom by means of a forcing pump, C, which draws the liquid from a 
reservoir, D. This liquid rises through the perforations and completely 
imuierses the confined wool, reaching at length a point above the perfo- 
rated follower, where it finds a lateral overflow tube. This conducts it 
into the still or alembic B. Here the bisulphide is volatilized by the 
heat of steam, which is introduced into the double bottom of the vessel 
and also into the midst of the liquid masses itself by means of a spiral 
tube within the alembic, not shown in the figure. When the process is. 
complete and the oil in the alembic is entirely free from the bisulphide, 
the stop-cock beneath permits to withdraw the product. Before this is 
done, however, steam is introduced into the mass of the impure oil by 
means of a second spiral tube, which is also not shown, and which is 
X3erforated with numerous holes. The design and the effect of this part 
of the process is to remove the last traces of the solvent. 

The vapor of the bisulphide is conducted from the alembic to the 
refrigerator J, where it is condensed in the spiral L, and is finally 
returned to the reservoir D. 

There is a stop-cock in the overflow tube which leads from A to B, 
through which may be withdrawn at any time a few drops of the liquid 
passing through the tube. When the specimen thus withdrawn, on evap- 
oration upon glass, leaves no trace of oil or other residnum, the opera- 
tion of the pump 0, may be suspended. For a short distance this tube 
is of glass, for the purpose of enabling the attendant to observe the 
color of the passing liquid. 

The process of solution being complete, communication with C is cut 
off by means of a stop-cock, and two other stop-cocks are opened. One 
of these j)ermits the liquid in A to descend through the spiral H to the 
reservoir D. The other allows air to be introduced into the upper part 
of A by means of the double-acting piston-blower E. The air, as the 
figure shows, may be drawn from D ; but the stop-cock beneath E is a 
three-way cock, and it allows the supply to be taken also from the 
atmosphere. In passing from E to A, the air is conducted through the 
jacketed tube M, and steam is introduced into the jacket to heat it to a 
degree sufficient to complete the volatilization of the bisulphide in A. 
But the first part of this operation, which consists in the mechanical 
expulsion of the bulk of the liquid in A, may be conducted without heat. 
The cock in the tube leading from A to H is a three-way cock, as well as 
that beneath E. At the close of the operation, the air blown through 
may be discharged into the atmosphere without passing through H. In 
that case it is conducted, by a long tube not shown, out of the building, 



320 PARIS UNIVERSAL EXPOSiriON. 

in order that any disagreeable odor which may accompany it may not 
annoy the attendants. The two spiral tubes, H and L, pass out of the 
refrigerator J, before entering the reservoir D. At these points they 
are provided with small stop-cocks, not shown, to permit the examina- 
tion of the substances passing through them. Into each of these tubes, 
also, as into the one leading from A to the alembic, is introduced a short 
glass tube as a part of its length, so that the interior of any one of them 
may be inspected. 

There remains one additional portion of the apparatus to be men- 
tioned, which is the gasometer G-. While the process is proceeding with- 
out any communication with the atmosphere, the volume of the confined 
air may vary with the temperature, or with the compression in A, and 
the volatilization of the bisulphide will also add something to the bulk 
of the aeriform mass. The gasometer, which may be, as represented, of 
the bellows form, or may be the ordinary bell and cistern, will serve to 
keep the capacity of the apparatus properly adjusted to the varying vol- 
ume of the contents. 

The boiling point of the bisulphide of carbon is 48° C = 118° F. If 
the air introduced into A is therefore heated to 70° or 80° C, the vola- 
tilization will be rapid 5 and this temperature does not affect injuriously 
either the structure or the color of the wool. 

A considerable economical advantage is obtained by this process, in 
the mere recovery to use of considerable quantities of wool which have 
been ruined by the pitch employed in marking. The animal oil sepa- 
rated has also some value. 

But the same process employed to dissolve the oils contained in the 
strappings of machine cards in factories, which amounts to one-third of 
the entire weight, is the source of a considerable saving. This oil is what 
has been added in previous stages of the manufacture, and after being 
thus recovered it may be used again. 

The wool which has been freed from oil by the process above described, 
on being subjected to the operation of the picking and beating machines 
preliminary to carding, yields a large proportion of fine fragments, or 
what may be called wool dust ; said by Mr. Payen to amount to forty- 
two per cent, of the total weight. This is valuable as a fertilizer in agri- 
culture, and is so turned to account. Under former modes of treatment, 
it was a total loss. 

But the application of the process above described has been more 
recently extended to a great variety of purposes. Tims, when the pitchy 
glycerine deposits, formed during the saponification with sulphuric acid 
— which is made a preliminary to the distillation of fatty bodies— are acted 
upon by the bisulphide, they yield a considerable quantity of stearine. 
amountiug to eighteen or twenty per cent, of their weight. The waste 
grease of the kitchen, the exudations which take place from the axles of 
vehicles or the journal boxes of machinery, and all similar forms of oils 
and fats, contaminated by impurities which, though they form but a small 



EXTRACTION OF OILS. 321 

part of the weight, destroy entirely the value, are completely restored 
by this process, which recovers the valuable portion, and leaves the impu- 
rities behind. Bags, swabs, and fibrous materials of any kind, which have 
been employed in cleaning- machinery or the parts of locomotives which 
it is necessary to oil, soon become saturated to such an extent that they 
are commonly thrown aside as useless ; but these give up a large amount 
of oil to the solvent employed in the new process, which is in itself a gain ; 
and the process also gives to the rags themselves a value which they had 
lost, since it permits them to be re-employed for the same purposes as 
before, or to be used in the manufacture of paper. In the direct extraction 
of wax by pressure, there is left in the solid residue a proportion of twenty 
per cent, of valuable material which may be recovered by solution in bisul- 
phide of carbon. This does not render the residue unfit for use as a ferti- 
tilizer, (the purpose to which it is commonly applied,) but rather improves 
it. Sawdust which has been used for the filtration of oils purified by sul- 
phuric acid, yields to this process fifteen to eighteen percent, of its weight. 
The acid impurities separated from oils in the process of purification by 
agitation with a small proportion of sulphuric acid, furnish by proper 
treatment with bisulphide of carbon half their weight of pure oil. Bones 
of animals obtained from the shambles, from the streets, from kitchens, 
and from various other sources, are used to the extent of many millions of 
pounds annually in every country, for the manufactures of glue and of 
animal charcoal. These are usually to some extent exhausted of their 
oils by boiling, before being used in the manufactures for which they 
are intended ; but the boiling separates only six or seven per cent. , while the 
bisulphide process extracts ten or eleven. The oil-cakes which are formed 
in the mechanical process of the expression of oils from seeds of various 
kinds furnish, as mentioned above, a large proportion of oil which the 
press has left behind. These cakes are sometimes broken up, reduced 
to powder, and pressed again with the aid of heat. But the labor of the 
second compression is greater than that of the first, and the product is 
less, while it still leaves the residue unexhausted. The cakes have a 
value as food for animals. It was at first supposed that the complete 
removal of their oil would injure them for this use, but experience has 
shown this impression to be an error. It is asserted by Messrs. Schlinck 
and Butsch, the exhibitors mentioned above, to have been fully proved 
by experiments on a large scale, already made, that in regard to the pro- 
duction of milk, butter, and flesh, the residua from which the oil has 
been thoroughly extracted are far superior to the pressed cakes, and that 
they retain their good qualities as food for animals, though kept long in 
store. The compacted masses left in the extraction of tallow or lard by 
pressure, furnish twenty per cent, additional, when treated with bisul- 
phide of carbon. The residue from the compression of cacao gives a sim- 
ilar increase of product on similar treatment. Finally, the marc of olives, 
as exemplified in the exposition of Mr. Deiss, furnishes quantities of 
excellent oil, which the press fails to separate. 
21 I A 



322 PARIS UNIVERSAL EXPOSITION. 

The peculiarity of the industry of Messrs. Schlinck and Eutsch is, that 
they do not take the trouble to use the compression process at all in their 
treatment of the oleaginous seeds from which their oils are obtained ; 
that is to say, they do not first extract a portion of the oil by pressure, 
and then subject the residuum to the action of the solvent, as has been 
done by others before them. It appears to them that if the bisulphide 
is capable of supplementing profitably the work of the press, it can per- 
haps perform the whole work more profitably still. Their experience 
demonstrates the truth of this supposition. They show specimens of oil 
before and after refining, obtained from American, Egyptian, and Italian 
cotton seed, from German flax seed, from rape seed, from poppy seed, 
from sesame, from Eussian sun-flower seed, and from the nuts of the 
beech. In appearance their refined oils are all that could be desired — 
being colorless and limpid as water. In the refining of their oils, they prac- 
tice a method of their own for which they claim peculiar merit, without 
stating what the method is. They state, however, what it is not, affirm- 
ing that it involves the use of neither acids nor water — reagents which, 
as they assert, are indispensable in the refining of any oil extracted by 
pressure. For this reason they further claim a special superiority for 
their drying and their lubricating oils j since the absence of water causes 
the drying oils to become rapidly inspissated on exposure, while the lubri- 
cating oils are entirely free from any trace of a reagent capable of attack- 
ing metals. These claims are given as stated, no opportunity having 
presented itself for experimentally testing their validity. If they are 
well-founded, this process possesses the double value of seeming in an 
important branch of industry a product which is at the same time more 
abundant in quantity and better in quality than it has been heretofore 
possible to obtain. 

YI.—EOBEET'S DIFFUSION PEOCESS FOE SUGAR. 

Among the improved industrial processes which have recently originated 
in Europe, but have not as yet come into general use, there is one having 
considerable interest for our own country, of which the object is to secure 
a more effectual extraction of saccharine matter from beet-root and the 
sugar-cane than has been found hitherto practicable. This process, called 
Eobert's diffusion process, was invented a few years ago in Austria, and 
it has been more recently pateuted in England by Mr. Mmchin, the man- 
aging partner of the Aska Sugar Works, in the East Indies. Though it 
was represented at the Exposition, it escaped the notice of the present 
writer, who failed, therefore, to become personally acquainted with it : 
but the reports which have appeared of the experiments made with it. 
and their encouraging results, give it an importance which justifies the 
introduction here of the following succinct account of its history and 
present promise, derived from the London Engineering : 

"We have repeatedly drawn the attention of our readers to the inter- 
esting and highly scientific process for extracting sugar from the cells of 



EXTRACTION OF SUGAR BY DIFFUSION. 323 

plants, invented by Mr. Robert, in Austria, and patented in this country 
by Mr. F. J. Y. Minchin, the managing partner of the Aska Sugar 
Works, in the East Indies. This process has been brought before the 
public at the Paris Exhibition in the form of a collection of specimens 
illustrating the entire manipulation as applied to sugar-cane, and the 
results obtained in actual, though not as yet in completely organized, 
practice. The collection of Mr. Minchin's samples is placed in the Indian 
department close to the other exhibits of sugar from India, with which 
it contrasts very remarkably in many respects. We may repeat here 
wherein Mr. Robert's process consists. The plants are cut up into thin 
square slices by means of very sharp and clean cutters so as not to destroy 
the cellular structure of the plant, but only to produce a large surface 
on which the liquids employed for extraction can act. The slices are 
filled into large vessels and covered with water at an elevated tempera- 
ture, the precise temperature used varying with the circumstances of the 
case. The water in contact with the slices of the beet-root or cane 
extracts from the cells of the plant a certain proportion of sugar by the 
natural and spontaneous process of endosmosis andexosmosis — a process 
which is known to take place with all organic membranous and cellular 
structures, and which consists in an exchange of all liquids placed in 
contact with the membrane at opposite sides. The contents of an organic 
cell surrounded by water are in this manner mixed or exchanged with 
the outer liquid, so that a cell containing a solution of sugar, and sur- 
rounded by pure water, will after a certain time contain a weaker 
saccharine solution, while the water outside will have taken up some of 
the sugar contained in the cell. If carried to the extreme, the liquids 
will exchange contents until the same mixture or solution will exist both 
inside the cell and outside. 

"Taking advantage of this property of organic substances, Mr. Robert 
combines a series of several vessels all filled with beet-root or sugar- 
cane slices, and passes water through them in a systematic order and 
succession. The fresh water, if passed over fresh cane, would be capa- 
ble of extracting one-half of the contents of the juice from the plant, 
and the second half could be further reduced by another quantity of 
fresh water to one-half of its amount, while the solution containing the 
first half is capable of taking up another proportionate part of sugar 
from fresh cane. The order followed by Mr. Robert is therefore to let 
the most concentrated solutions pass over the fresh cane, and to pass 
weaker and weaker solutions over the plants as their contents of sugar 
become more and more reduced, so that the fresh water comes first into 
contact with the slices which have been longer under treatment, and are 
consequently very poor in sugar, and afterwards it passes in succession 
over slices containing more and more sugar, until it at last comes upon 
fresh cane, and attains the highest degree of concentration which the 
process is capable of aifording. A number of such vessels combined in 
this manner, and working in rotation so as to make the process con- 



324 PARIS UNIVERSAL EXPOSITION. 

tinuous, is called a battery ; and there are, as a rule, six or eight vessels 
combined into one such battery for diffusion. For the manufacture of 
beet-root sugar, Mr. Robert's process has now been in operation for 
about four years, and there are about thirty factories now using this 
system in Germany, Austria, and in Eussia, with the most complete com- 
mercial success. There are some other works of the kind now in course 
of construction in Belgium, and others are about to be established in 
France very shortly. 

" The success of Mr. Robert's process with beet-root sugar was, how- 
ever, not sufficient to prove its applicability to the extraction of sugar 
from cane. This has now been established by Mr. Minchin. The Aska 
Works have produced about sixty tons of sugar from fresh sugar-cane by 
the diffusion process. Mr. Minchin started his works in March last and 
commenced operations with four machines for cutting the cane into 
slices, which had been sent to India from Austria, these machines being 
the manufacture of Messrs. Wannick & Jelliuck, engineers of Briinn. 
These four machines were driven by an engine of twelve nominal horse- 
power ; but there was a surplus of power under these circumstances, as 
the actual requirements of these machines scarcely exceeds one horse- 
power each. The slices produced by the machines were removed by an 
Archimedian screw moving in a trough, and they were delivered to an 
elevator strap which lifted them up to the top of the diffusion vessels. 
There they were filled into a wagon constructed for enabling the attendant 
to weigh the quantities of sugar-cane used, and from the wagon the mate- 
rial Avas discharged into the vessels in proper rotation. The vessels, six- 
teen in number, and arranged in two sets of eight as two complete bat- 
teries, are made of wood, in the shape of large casks or vats, each capable 
of holding two and a half tons of cut cane and about the same weight of 
water. There is an addition of about fifteen pounds of slacked lime made 
to the water, in order to neutralize the acid contained in the juice of the 
sugar-cane. The temperature at which the diffusion was carried out at 
Aska was 155° to 165° F, the fresh cane being warmed by steam before 
the liquid was run over it, so as to prevent the mixture from cooling 
down too much. The time allowed for diffusion was forty to fifty-five 
minutes, the same time being required for filling one of the vessels with 
fresh cane ; but it is the intention of Mr. Minchin to reduce the time of 
diffusion in future campaigns very considerably. The diffusion was 
found to be practically complete with five vessels: i. c. there was so little 
sugar left in the cane slices after having been treated in this manner 
with five successive charges of liquid, that the process was allowed to 
stop there. The collection of samples brought to the Exhibition by Mr. 
Minchin contains some sugar-cane cut into slices for diffusion by the 
machinery at work in Aska. The cane contained about ninety per cent. 
of juice when fresh, and this juice has a density of about 15° on an 
average. The diffusion liquid produced from this cane by the new 
process showed an average density of 14°, proving how near the eoueen- 



EXTRACTION OF SUGAR BY DIFFUSION. 325 

trationof the diffusion liquid can be brought to that of the natural juice 
contained in the plant itself. The notion that the diffusion process 
requires the evaporation of weaker solutions of sugar than are obtained 
by the ordinary mode of extraction is, therefore, proved to be correct 
only in theory, since the difference in practice is so small that the results 
are not affected by it. There have been also some comparative analyses 
made both of the contents of the cane juice when extracted by mechanical 
pressure and of the diffusion liquid obtained from the same kind of cane. 
These trials were conducted very carefully, and the specimens of both 
modes of extraction were taken from the same lots of plants, so as to 
avoid any accidental sources of error. The juice extracted from the 
cane by pressure was found to contain 0.62 per cent, of foreign matter or 
impurities, while that obtained by diffusion had only 0.43 per cent, of 
such substances. The nature of these impurities in the two kinds of j nice 
produced by the two modes of extraction is one of the most important 
points in favor of the diffusion process. The cellular structure of the 
plants being preserved by this mode of extraction, it follows that the 
nitrogenous organic substances, which are not sufficiently soluble in 
Avater to be drawn out by diffusion, are left within the cells, and remain 
in the trash, so that the diffusion juice is much purer, and the raw sugar 
produced from it perfectly clean and white. This fact has been fully 
established by the products of Mr. Minchin's first campaign. The raw 
sugar produced at Aska, and now exhibited at Paris, is of a surprising 
purity and beauty. It is placed close to some specimens of refined sugar 
from several other Indian sugar factories, and it surpasses even these 
refined sugars in beauty of color and in the transparency of the crystals. 
The analysis of this raw sugar made by diffusion gives 96.9 per cent, of 
sugar, 2.94 per cent, of water, and 0.16 per cent, of foreign substances. 
Mr. Minchin's exhibition contains samples of the different kinds of sugar 
obtained from his diffusion liquids by the successive boilings ; and the 
analysis of each specimen, which is attached to the corresponding sam- 
ple, shows an equal degree of relative purity as compared with the analo- 
gous products of the usual process of extraction by mills. This part of 
Mr. Minchin's exhibition is devoted to the question of quality as regards 
the products of the diffusion process, and in regard to this point the 
superiority of this new mode of extraction seems to be established with- 
out further doubt. The other specimens shown by Mr. Minchin refer to 
the other equally important point, viz : the quantitative results, or the 
economy of the diffusion process. The economy in first outlay for 
machinery and plant of course requires no illustration. Perhaps the 
whole plant for the diffusion process may be erected in any one of our 
colonies for the same sum of money which the making and transporting 
of the base plate of a sugar-mill for an equal production would require. 
The relative economy of the other manipulation may be gathered from 
the description of the mode of working, and it is of less importance. 
The main point in question, and the only one about which doubts were 



326 PARIS UNIVERSAL EXPOSITION. 

entertained, is the quantity of sugar which can be extracted from the 
cane, and ultimately utilized or 'bagged' as crystallized sugar. On 
looking to this point, we find in the Exhibition a sample of the cane- 
trash after extraction, and we find the analysis of its contents given by 
the chemist of the Aska Works. We also learn that Mr. Minchin keeps 
a quantity of similar cane-trash at the disposal of any chemist who 
desires to verify the analysis. The diffusion-trash varies in its contents 
between 0.112 and 0.49 per cent, of sugar, showing that the extraction 
by diffusion goes much further, and is much more complete, than any 
other method now in practice. Mr. Minchin has further established this 
fact by making diffusion sugar from the cane-trash left by the ordinary 
mode of extraction by sugar-mills. A sample of such sugar is exhibited 
at Paris, and it shows that the diffusion process may be effectively com- 
menced when the ordinary process finds its limits from want of efficiency. 
By all this it may be considered as an established fact that the diffusion 
process is applicable to sugar-cane, and that its advantages, both as 
regards quality of the product and economy of manufacture, are very 
considerable. Exact figures and percentages of the relative quantities 
of sugar made from a given quantity of cane on a large scale have not 
as yet been arrived at by Mr. Minchin. The Aska factory was not 
originally laid out for the manufacture of raw sugar, but simply as a 
refinery, and sufficient means for evaporating the large quantities of dif- 
fusion juice made in this season were therefore not at Mr. Mmckin's com 
maud. It was thus found necessary to use only a part of the liquid for 
sugar-making, and to utilize the rest for the manufacture of rum and 
other articles. It will therefore require another season to collect reliable 
data of the relative yield of sugar to be obtained from cane by the dif- 
fusion process. Even without these precise statistical figures, the 
advantages of the process and its applicability to sugar-cane are, how- 
ever, sufficiently perceptible at present. As a proof of this, we may 
state that the international jury at Paris has awarded a gold medal to 
Mr. Minchin for his remarkable and important exhibits. There is one 
inqiortant point yet to be mentioned with regard to the diffusion pro- 
cess, viz : the utilization of the cane-trash as a fuel. This seemed to be 
a difficulty at the outset, since it was thought that the cutting of the cane 
into such small slices as are required for diffusion would prevent the 
trash from being used as a fuel. This has, however, been disproved by 
experience. The trash can be dried by simple exposure to the sun, and 
it is found to dry much more easily than fresh cane. After this it burns 
perfectly well upon a suitable grate, so as to be fully equal in this respect 
to the trash from the cane-mill. The Aska factory is now about to be 
considerably enlarged, and fitted out with complete apparatus for sugar 
manufacture by the diffusion process on a very large scale. We also 
understand that the diffusion process is shortly to be introduced in Cuba 
and in some other sugar-cane growing countries." 



VITREOUS ENAMELS FOR METALS. 327 

VIL— ENAMELLING AND BRONZING. 

PLEISCHL'S ENAMELS. 

Many inventors have occupied themselves with the endeavor to dis- 
cover a vitreous enamel for metals which should combine the properties 
of durability, freedom from noxious ingredients, and unalterability by 
contact with the substances contained in the vessels to which it is applied. 
Enamels possessing these qualities to a great degree are already in use 
in this country, but there are none which will bear flexure or rough 
treatment to any extent without cracking or scaling off, though they 
may bear for a time sufficiently well the ordinary variations of heat to 
which, for culinary purposes, they are subjected. Something apparently 
very superior to this was exhibited in the Austrian section of the Expo- 
sition by Mr. Adolph Pleischl, of Vienna. Plates of copper were shown 
by him covered with a glassy coating, which bore exposure to heat and 
resisted the action of acids, and possessed at the same time the addi- 
tional property quite as important as either of these, of allowing the 
the plate to be bent to an acute angle without either scaling or cracking. 
Many articles designed for domestic use or for chemical purposes were 
embraced in the collection of Mr. Pleischl, and according to the state- 
ment of the exhibitor, it had been thoroughly tested for both these pur- 
poses with results entirely satisfactory. According to the same authority 
this enamel is free from lead or zinc. It is not liable therefore to the 
serious objection to lead glazes, of contaminating liquids contained in 
the vessels coated with it with poisonous salts. It endures very rough 
treatment; bears hard scratching with a knife without losing its polish 
or showing any trace of the implement ; may be heated to any degree, 
even to redness, and it continues to be perfectly sound, however the ves- 
sel may be indented or distorted. 

No information could be obtained as to its composition. A letter 
addressed to Mr. Pleischl himself, at Vienna, elicited only some interest- 
ing statements as to its durability, but none as to the materials used in 
preparing it. It has been in use in the imperial-royal general hospital 
and in the foundling hospital at Vienna for many years. The large 
kettles in the laundry of the first of these establishments, after having 
been in daily use for years, and during sixteen hours each day, show no 
signs of change. In the second, the great iron pots of the cook-house 
after nine years of constant service, are equally unchanged. It has been 
used for purposes of galvanic gilding without being affected by the 
chemicals employed. It bears a dry heat to redness, as above stated, 
the only precaution necessary to be taken being not to cool it suddenly 
by contact with water. It is harder than glass, which it scratches, and is 
not even scratched by scouring with sand, so that the vessels coated 
with it may be cleansed in the most thorough manner that may be 
desired. And finally, if after many years of hard service the vessels 
covered with it begin to fail, it admits of repair. The bottoms can be 



328 PARIS UNIVERSAL EXPOSITION. 

replaced and enamelled anew, restoring at once the sightliness and the 
usefulness at the same time. Mr. Pleischl also shows specimens of calk- 
ing pitch for ships, which have a very powerful adhesion to wood, are 
not affected by sea- water, and have the great advantage of not being 
affected by the heat of the sun. It is stated that the Austrian navy has 
introduced this material in preference to all others hitherto employed, and 
that it has proved very satisfactory. An article similar in appearance 
to this calking pitch, but different in its composition, is Mr. PleischTs 
varnish for iron vessels and pipes, which is now largely used in Germany 
for water-tanks, buckets, and other vessels intended for storing fresh 
water. This varnish is applied in a liquid state, and' dries after a few 
hours, and is perfectly insoluble in water and impervious to liquids. It 
stands a very considerable pressure without cracking. Some trials made 
at Vienna show that a leaky cast-iron pipe, when covered with a coat- 
ing of this paint, Avithstood a pressure of one hundred and fifty pounds 
to the square inch without showing the smallest signs of porosity. There 
can be no doubt that a material of such useful qualities, and which, to 
judge from the price-list issued by the maker, can be produced at very 
moderate rates, is likely to find a very wide range of application. 

werxer's patext glaze for casks. 

Another very excellent coating for the interior of casks was exhibited 
by Messrs. J. Werner & Co., of Mannheim, Baden. The magnitude and 
importance of the beer-brewing industry of the United States render 
every such really efficacious invention a matter of interest. In regard 
to this material, as to the former, the composition is unknown, but the 
following statement as to its merits is given in the language of the invent- 
ors, in reply to an application for information : 

"Our patent glaze is not only a substitute for the pitch used in brew- 
eries hitherto for the purpose of isolating the inside of casks or kegs : it 
also gives to the brewer the most reliable security, when applied on fer- 
menting tubs or coolers, that the process of fermenting, which is at all 
times a vital question and of the greatest importance for the brewer, 
accomplishes itself in a faultless manner, which is far superior to any 
other mode existing. 

"The glaze was invented in 1860 by and patented to Mr. Werner, and 
has since that time introduced itself in several thousands of breweries 
all over this continent. 

" The patent glaze is superior to any pitch or rosin ever known, because 
it never cracks or comes off; it is put on cold and with a bristle-brush : 
when extensively used, it is cheaper than pitch : it is a real preservative 
for casks and kegs ; it communicates not even the slighest taste or smell 
to the beer. Whereas, on the other hand, pitch or rosin always cracks 
or comes off in pieces; must be burnt in, and has often been the cause 
of loss of life and property; it is very expensive, because the manipula- 
tion of burning it in absorbs and destroys the strength of the wood, so 



GLAZE FOR CASKS BRONZED IRON. 329 

that in a couple or three years new casks or kegs are unfit for further 
use $ it ever gives to the beer a sappy, more or less disagreeable taste and 
flavor. 

"All periodical papers and books treating on beer-brewing have paid 
great attention and warmly recommended the patent glaze, not, how- 
ever, in the manner and way of 'puffing, 7 but on the strength of a pre- 
vious strict trial and impartial examination. Such papers are : 

u Der Bierbrauer, edited and published by Doctor Habich, at Wies- 
baden 5 Ber Bayerisclie Bierbrauer, edited by Doctor Lintner, professor of 
chemistry and director of the Royal Brewing Academy at Freising, near 
Munich, Bavaria, and published by E. H. Grunimi, at Munich; the 
Beutsche Industrie Zeitung, edited and published by Mr. Robert Binder, 
at Chemnitz, in Saxony. 77 

The inventors are desirous to introduce this article into the United 
States, and express the belief that "any person who takes hold of this 
matter and is sustained by us in regard to the purchase of raw material, 
as well as through the high recommendation of European firms in brew- 
ing, of the first reputation, will realize a fortune in the United States in 
less than three years. 77 

TUCKER 7 S BRONZED IRON. 

One of the products in the American department, which was looked on 
with particular favor, was exhibited by Mr. Hiram Tucker, of ISTew York, 
under the name of bronzed iron. The objects in the collection of Mr. 
Tucker were certainly very beautiful, resembling very closely real bronze ; 
and the relative cost is so much in favor of these imitations as to insure 
them an extensive popularity. They are said to have been already well 
received in France. The following notice of this useful invention is from 
Engineering: 

"The name bronzed iron is given to Mr. Tucker 7 s productions on 
account of their having the color and appearance of bronze castings, 
although the articles are not coated with bronze, nor with copper, or any 
other metallic compositions such as are usually employed in the manu- 
facture of imitation bronze. Mr. Tucker 7 s invention consists in treating 
the iron castings with vegetable oil at an elevated temperature, so as to 
produce upon the metallic surface a skin of oxide, which, in combination 
with the decomposed organic substance, gives the desired color and 
appearance. The castings, when finished and cleaned, are carefully 
covered with a liquid oil all over their surface, and particular attention 
is paid to the removal of all surplus oil, so as to leave only an extremely 
thin coating upon the metallic surface. In that state the iron casting is 
ready for the oxidizing process. It is brought into a stove heated to the 
temperature which decomposes the oil without charring it. This tem- 
perature is the same which will impart to cast iron a blue tint when 
exposed to it, with a clean metallic surface. At this temperature, there- 
fore, the double process of oxidization of the iron and of decomposition 



330 PARIS UNIVERSAL EXPOSITION. 

of the oil takes place simultaneously, and the castings are covered with 
a brown coating of oxide, which remains fixed to the surface with great 
durability, protecting the iron from further oxidation, and having the 
same lustre and metallic appearance as real bronze. The durability of 
this 'bronzing 7 is very considerable, and even those spots which, by 
constant wear, lose their superficial coating of oxide after some time, 
maintain the original brown color, since a new coat of brown oxide of 
iron is formed under the influence of the atmosphere, which makes the 
difference between the injured parts and those which have maintained 
their original color scarcely perceptible. Mr. Tucker's bronzes are, of 
course, much cheaper than real bronze articles, and they also compete to 
advantage with imitation bronze, over which latter material they also 
present the advantage of greater durability and beauty of form, since 
good cast iron fills the moulds with extreme accuracy, and allows of the 
reproduction of the finest mouldings given to the matrix. Mr. Tucker 
has started a manufacturing company for his bronzes at Boston, and is 
now about to introduce this manufacture into France." 

PARKESINE. 

A very remarkable product, called by its inventor, Mr. Alexander 
Parkes, of Birmingham, England, after his own name, was exhibited in 
the British department, in the form of buttons, knife-handles, combs, and 
various other articles of common use, of which it is the material. In 
some respects this substance resembles ebonite, or hard rubber ; in oth- 
ers, bone or ivory ; and in others, horn. It admits of being made color- 
less and translucent, or opaque and colored, at pleasure. The inventor 
has not fully disclosed the process of manufacture, or stated all the mate- 
rials which enter into the composition, but asserts that it is cheaply 
made, the bulk being composed of substances having little value for other 
purposes. Cellulose or lignine, wholly or partially converted into the 
soluble form, is admitted to constitute the basis ; but refuse cotton, or 
rags, or paper, may serve for the purpose, as well as articles of greater 
commercial value. This is combined with drying-oil and with other sub- 
stances not named. Before the combination the oil is solidified by means 
of chloride of sulphur, united in varying proportions with naphtha or sul- 
phide of carbon, the degree of hardness or flexibility of the product 
depending on the proportion used. By varying the materials every 
variety and degree of brilliancy of color may be obtained, and also every 
degree of hardness or flexibility, transparency, or opacity. When per- 
fectly opaque and white, it is very beautiful. 

This substance yields easily to the tool of the workman, and can be 
made to assume any desired form in the lathe, or under the hand of 
the carver. It may be made to imitate perfectly, wood, shell, horn, or 
ivory. It is unalterable under exposure to the weather: can be com- 
pressed in moulds into the form of ornaments or objects of use. such as 
the handles of knives, gravers, and tools in general : and can be com- 



PAEKESINE. 331 

bined with other materials so as to impart to them its useful properties. 
Being a non-conductor of electricity, it is available for the insulators of 
telegraph lines, or the insulating portions of electrical apparatus of all 
kinds. One of its most important advantages is the property it pos- 
sesses of forming a solution which serves perfectly to unite different por- 
tions into one mass, or to repair objects composed of it which may have 
been fractured by accident. In its flexible form it has been recently 
employed as a substitute for India-rubber in gas-pipes. 

If the statements made in regard to this substance are correct, it can- 
not fail to come extensively into use. An examination of the articles 
which were on exhibition, manufactured from it, was sufficient to show, 
that in regard to strength, beauty, and apparent serviceability, it is not 
inferior to any of the substances which it is made to resemble ; but as to 
its original cheapness, or the durability of its good qualities, it was of 
course impossible for the cursory observer to judge. From the fact that 
the invention dates back to a year earlier than that of. the Exposi- 
tion of 1862, in London, it would seem as if, in regard to these particu- 
lars, some room remains for doubt. 



CHAPTER X. 
DIVING AND RESPIRATORY APPARATUS. 

Submarine armor — Antiquity of its use — The diting-b ell— -Diving apparatus 
oftheNew York Submarine Company — Diving apparatus of Eouquayrol and 
Denayrouze— Dlfference of pressure within and outslde of the regula- 
tor — Form of air pimp employed— Use of apparatus for cleaning bottoms 
of vessels— Life-saying respiratory apparatus. 

I.— DIYI^G APPARATUS. 

Submarine armor, with provision for the respiration of divers at con- 
siderable depths beneath the surface of the water, and designed to be 
used with or without diving-bells, is not a new invention. To say nothing 
of the earlier forms of apparatus of this kind of which descriptions remain. 
but which were apparently little more than projects, the diving dress of 
Klingert. of Breslau. appears to have been very successfully used as 
early as 1798. This consists, first, of a metallic cylinder with a hemi- 
spherical top. intended to cover the head and to come down below the 
shoulders of the diver : and. secondly, of a cylindrical metallic protection 
for the chest, meeting the head cover in a close joint, which was secured 
by an exterior jacket of leather bound firmly at top and bottom to the 
two cylinders by means of metallic hoops or bands secured with screws. 
The arm holes were cut in part out of the upper and in part out of the 
lower cylinder, the sleeves of the jacket covering them, and the sleeves 
themselves were made sufficiently tight just above the elbow to prevent 
the" entrance of water, the fore-arm remaining uncovered. Leather 
drawers, extending to the knee and strengthened against the pressure of 
the water by an interior frame of iron, completed the dress. These, like 
the sleeves, were secured against the admission of water by tight liga- 
tures, and at the top were connected with the metallic chest protector 
by means of a firmly screwed metal hoop. Glazed apertures in front of 
the eyes permitted the diver to look about him. Respiration was pro- 
vided for by means of flexible tubes extending above the surface of the 
water, one for the purpose of admitting the air to the lungs, and the 
other for the purpose of discharging it. The first terminated within the 
helmet, in a mouth-piece of ivory, and. the mouth being kept always 
closed, exhalation took place through the nostrils, the discharge air 
escaping through the second tube. To counteract the buoyancy of the 
apparatus the diver suspended weights to his waist. These being properly 
adjusted, he was able to walk about upon the bottom, and to use his arms 
tor the performance of any required work. 



DIVING APPARATUS SUBMARINE ARMOR. 333 

The disadvantages of an apparatus of this kind in the case of any con- 
siderable depths are obvious. Though the head, chest, and limbs are 
protected, the extremities are exposed to the full pressure of the water; 
and this, not being counterbalanced by any corresponding pressure on 
the protected parts, must soon become intolerably painful. Yet, for 
moderate depths, it was practically found to be quite serviceable. 

Mr. Klingert endeavored, and in a measure successfully, to obviate the 
disadvantage just spoken of, by providing an air reservoir, to be sunk at 
the same time with the diver, and designed to furnish him with air under 
a compression corresponding with his depth. He gave to this reservoir 
a cylindrical form and a capacity of fifty-eight cubic feet, which he consid- 
ered to be a sufficient supply to last one man two hours. The cylinder was 
so ballasted as to float upright when filled with air of ordinary density, 
exposing only about one foot of its height above the water. But it was 
provided with a movable bottom in the form of a piston, which could be 
controlled by a rack and pinion worked by a crank. By operating the 
crank so as to drive in the piston, the buoyancy of the cylinder would be 
correspondingly diminished, and the whole apparatus would sink. The 
breathing tube of the diver was to be connected with this reservoir, and 
as it rested on the bottom, he could increase or diminish the density of 
the contained air at pleasure, by turning the crank. The air, after 
inhalation, could be exhaled into the reservoir again, or be permitted to 
escape through a properly arranged valve in the armor. The first mode 
would provide against variation of pressure, although attended with a 
gradual vitiation of the purity of the air. But as it is experimentally 
proved that the same air maybe safely breathed twice over, and as ordi- 
narily a man does not inhale more frequently than fifteen or twenty 
times a minute, nor receive into his lungs more than twenty-five or thirty 
cubic inches of air at each inhalation, it is proved by an easy calculation 
that the fifty-eight cubic feet of Mr. Klingert's reservoir would suffice for 
the support of a diver much longer than he claimed, even if no portion 
of it were allowed to escape after being breathed. 

Tonkin's submarine armor, employed early in this century on the Brit. 
ish coast, and especially in the recovery of valuable articles from the 
India ship Abergavennie, which foundered in 1804 near Weymouth, was 
in principle similar to Klingert's, but was stronger and more elaborate. 
It resembled very much the military armor of the early and middle ages, 
being formed of metal plates articulated with each other, but covered 
also with an exterior dress of water-tight leather, to secure against leak- 
age. The protection extended to every part of the person except the 
arms, the feet and legs being covered with iron boots, though the larger 
plates covering the body were made of brass. For the supply of air to 
the diver an elastic tube was employed, as in the case of Klingert's appa- 
ratus, communicating with an air vessel in a boat at the surface. Into 
this vessel air was thrown by a forcing pump until its elasticity was suf- 
ficient to counteract the pressure of the water. The diver employed no 



334 PARIS UNIVERSAL EXPOSITION. 

mouth-piece, but breathed the air within the case, permitting it to escape, 
as it became vitiated, through a valve provided for the purpose. To 
compensate for this loss the pump was kept in action, so as to maintain 
the pressure as nearly as possible uniform. A plate-glass window, eight 
inches in diameter and one inch thick, enabled the diver to see the 
objects about him, and to perform the work required. 

The diving-bell, a machine often used in subaqueous operations, and 
which requires no special provision for the protection of the divers per- 
son, seems to have been very early known, and is said, in fact, to have 
been employed among the Greeks of the time of Aristotle. Its earliest 
appearance in western Europe took place near the beginning of the six- 
teenth century. But it was more than two hundred years later that 
this contrivance was made practically available for use at any but very 
moderate depths. The pressure of the water necessarily reduces the 
bulk of the air contained in the bell in proportion to the depth of the 
immersion, so that at the depth of five or six fathoms the bell is half 
full of water. In 1715, the celebrated Dr. Halley suggested a simple 
mode of displacing the water by the addition of a fresh supply of air. 
His method consisted of sinking barrels containing air to a level a little 
lower than that of the bell, and afterwards discharging their contents 
into the bell by means of pipes proceeding from the top of the barrels, 
while water was admitted at the bottom. This expedient also sufficed 
to maintain the purity of the air in the bell; for, inasmuch as tbe por- 
tion vitiated by respiration would accumulate at the top, on account of 
its higher temperature, it could be from time to time discharged by 
merely opening a cock, while a fresh supply was received below. 

Dr. Halley also contrived a very ingenious apparatus to enable the 
diver to leave the bell and still to have the benefit of the air which it 
contained, without encumbering himself with any kind of armor except 
what may be called a species of helmet. This helmet was, in effect, 
nothing more than a smaller portable bell, covering the diver's head, 
and descending far enough for his security without embarrassing the 
motion of his arms; but entirely open below, and in the dimensions of its 
upper portion little larger than a cap. The front of this cap was strongly 
glazed, and, in order to prevent obscuration of the glass by the condensa- 
tion of vapor from the breath, the cap in front of the face was considera- 
bly enlarged or prolonged. A tube from the cap leading to the interior 
of the bell supplied the wearer with the necessary air. This tube was 
furnished with a stop-cock, at the command of the diver, for the purpose 
of regulating the flow of air ; an important consideration, since this flow 
would be from the bell to the cap or from the cap to the bell, according 
as the level of the water in the one or the other should be highest. When 
the diver, in leaving the bell, was obliged to descend beneath its rim. 
the water would, of course, fill the cap entirely, expelling all the air. 
unless the cock were closed. The same accident, in the absence of a 
similar precaution, would occur every time he descended to a lower level. 



DIVING APPARATUS — DIVING BELLS. 335 

in consequence of the inequalities of the bottom, or every time he had 
occasion to stoop. On the other hand, if he mounted to a level higher 
than that of the water in the bell, the flow of air into the cap might be 
greater than necessary for his comfortable respiration, or might be even 
wasteful, unless it were regulated by a partial cut-off. 

Important improvements upon the diving-bell of Dr. Halley were 
made at a period somewhat later, by Mr. Spalding, of Edinburgh. One 
of these was a simple provision against the possible accident of the over- 
turning of the bell by the irregularities of submarine rocks, or the spars 
of a sunken vessel, catching the edge of the bell on one side while the 
persons above continue to let it descend. This dangerous possibility, 
which experiment had proved to be very real, was provided against by 
suspending the weight employed as a sinker at some little distance below 
the bell, while the bell itself was only ballasted so as to stand upright, 
but made too buoyant to sink. By means of this arrangement the weight 
would first strike the rocks, and the progress of the descent would be 
arrested, until the divers could reconnoitre the nature of the surface 
beneath them. The bell could then be depressed to the point desired, 
by hauling on the weight. A simpler mode, however, was devised by 
Mr. Spalding for regulating the descent and elevation. The bell was 
made of considerably larger vertical dimensions than had been previously 
used, and a horizontal partition divided it into two chambers. The 
lower of these was occupied by the divers, while the upper was used as 
a regulator of buoyancy, somewhat on the principle of the air-bladder 
in fishes. When this was entirely filled with water, as it might be by 
opening a cock in the top for the discharge of any air it might contain, 
and another one at a lower point for the admission of water, the bell 
would descend. On the other hand, when entirely filled with air by the 
admission of air from the lower chamber while the water was permitted 
to escape from the bottom, the loss from the lower chamber being in the 
mean time supplied from the air-barrels above described, the apparatus 
became sufficiently buoyant to rise independently of any assistance 
from the persons at the surface. This last was a very important improve- 
ment, since it placed the divers beyond the reach of danger from the 
breaking or entangling of the suspending ropes. 

Hitherto the material employed in the construction of the diving-bell 
had been wood, and the form given to it had been that which is implied 
in its name. In 1788, or somewhat later, Smeaton, the eminent engineer, 
whose name is associated with so many of the important public works 
constructed in Great Britain toward the close of the last century, con- 
ceived the idea of substituting cast iron instead of wood, and of giving 
to the machine the form of a rectangular box. He also greatly increased 
its dimensions, making it four feet and a half in length and height, and 
three feet in width, with a capacity therefore of sixty cubic feet. He also 
discarded the method of supplying air by sinking barrels, and subsituted 
a forcing pump, by means of which he maintained a constant stream, 



336 PARIS UNIVERSAL EXPOSITION. 

which was conducted to the bell through a flexible tube. By adopting 
a material for the bell of so great specific gravity as iron, it became 
practicable to dispense with the weights which had been previously 
attached to the sides of the machine. The total displacement exceeded 
two tons. A weight was given to the bell approaching two tons and a 
half, a large portion of this weight being accumulated around the rim 
in order to secure stability in the upright position. 

The diving-bell in its perfected form will thus be seen to be a cumbrous 
machine, requiring a considerable force for its management. Its capa- 
bilities of usefulness are such that it will probably not be wholly super- 
seded by any other contrivance for facilitating subaqueous explorations, 
or the application of human labor to operations beneath the surface of 
the water ; but the difficulty and expense attendant on its use are such 
as practically to limit its employment to constructions of great magni- 
tude and to works of long continuance. For the ordinary purposes of 
diving, some description of armor for the protection of the person, which 
can be used under any circumstances, and without elaborate preparation, 
will be generally preferred ; and, indeed, without such armor, the use- 
fulness of the bell itself must be greatly restricted. The latest attempts 
to improve upon the apparatus for diving have related to diving dresses 
or diving armor, and to the means of providing for the comfortable 
respiration of the divers. 

DIVING APPARATUS OF THE NEW VORK SUBMARINE C03IPANV. 

There were exhibited at the Exposition of 1867 two descriptions of 
diving apparatus, either of them very superior to the forms heretofore 
in use, and each having merits peculiar to itself. One of these was 
exhibited by the New York Submarine Company, a corporate association 
organized for the purpose of undertaking submarine work of any descrip- 
tion, such as the construction of submarine foundations, the raising of 
sunken vessels, the buoying of vessels over bars or sand-banks, and the 
examination and repair of ships' bottoms, or of any existing permanent 
works covered by the water. The part of their apparatus which is 
designed for buoying and lifting operations is very simple, but is no less 
interesting. Heretofore, in such operations, boats, barges, or casks, in 
great number, have been lashed to the vessel to be lifted, after having 
been filled with water and submerged, and these have been rendered 
buoyant by removing the water, which, in the case of boats, is effected 
by pumping, and in the case of barrels by the use of the compression 
air-pump. The buoys of the New York company are huge canvas sacks 
coated with India-rubber, and externally strengthened and guarded by 
a network of strong cordage. Each has a capacity of five hundred and 
fifty cubic feet, and a lifting power, when inflated, of about fifteen tons. 
These buoys are connected together in pairs, one on each side of the 
vessel to be lifted, by means of chains which extend beneath the keel. 
In order to facilitate the repairs of the buoys, each is fitted at the upper 



SUBMARINE ARMOR AND BREATHING APPARATUS. 337 

end with a ring, to which a copper plate is secured, so that it can be 
readily removed for giving access to the interior. To this manhole plate 
is fitted a safety-valve for relieving the buoy of the overpressure as it 
rises to the surface ; and the lower end of each buoy is also fitted with 
a metallic ventilator and safety-valve, both for convenience in handling 
and to prevent the bursting of the buoy in case of its rising too rapidly 
to be relieved of the internal pressure by the upper valve alone. 

The buoys are of course attached in a collapsed condition to the vessel 
to be lifted. Air is then admitted to them from the reservoirs in the 
attending vessel, in which there has been accumulated a great volume, 
reduced to the bulk of about five hundred feet, under a pressure of thirty- 
three atmospheres. The reservoirs, which are six in number, are kept 
charged by means of powerful compression pumps, one of which, capable 
of delivering one hundred and twenty cubic feet per minute, is employed 
to commence the compression, and the other, of smaller capacity, to carry 
up the pressure to the maximum. 

The buoys, before inflation, are fixed to the sides of the vessels by 
divers, who are fitted out with the submarine armor and breathing 
apparatus which is peculiar to this company. This armor consists, for 
moderate depths, of a strong helmet of metal, cushioned in the interior, 
and having a plate-glass window in front, and a water-proof dress entirely 
enveloping the person, which is secured to the helmet very much in the 
way employed by Klingert. This dress is sufficiently weighted to sink 
the diver in the water, and to enable him to stand firmly when it is 
necessary to rest upon the bottom. In order to provide for respiration, 
an air reservoir is fastened upon his back in the manner of a knapsack, 
into which a sufficient amount of air has been compressed to serve him 
for several hours. This air is conducted into the interior of the dress 
by means of a pipe provided with a cut-off valve under the diver's control. 
A cock on the top of the helmet permits the discharge from time to 
time of the air which has become foul by breathing. 

For depths sufficiently great to make the compression of the folds of 
the dress against the person an inconvenience, there is provided what is 
called an inside protector, formed of a series of ribs or rings surrounding 
the person and the lower extremities, which prevents collapse. 

The diver also wears, secured beneath his arms, a pair of buoys, 
designed to raise him in the water at his pleasure. These are water-tight 
sacks, resembling the India-rubber life-preserver, and are inflated, when 
necessary, from the reservoir at his back. 

A printed description of the apparatus furnishes the following addi- 
tional particulars : 

"In this dress and outfit the diver is independent of any connection 
with the surface, and, by means of appliances fitted in his helmet, he is 
able to take his own bearings and directions, and keep his own time. By 
the inflation of the peculiar life-preserver with which he is provided, the 
diver can ascend to the surface at pleasure, and when there, will be head 
22 i A 



338 PARIS UNIVERSAL EXPOSITION. 

and shoulders out of water, and can open his helmet himself. This diving 
armor removes the danger of suffocation incidental to the usual method 
of pumping the air to the diver, arising from the kinking or injury of 
the hose which conveys the air down to him, and from the imperfect 
action of the pump. By means of his buoys he can rise or sink to any 
depth and there suspend himself. This improvement is of great value 
for the examination of vessels' bottoms. The security of the diver for his 
air, both for breathing and for remounting to the surface, maybe exem- 
plified by the fact that a diver, wearing this dress, has, at the depth of 
forty feet, sent up a column of air which raised a fountain or jet three 
feet in height at the surface. Ordinarily, a knapsack or reservoir suffi- 
cient to maintain a four hours' supply of air for the diver will be large 
enough. 

" For facilitating operations under water, the Submarine Company 
employ a submarine lamp, which is also fed by compressed air, and 
requires no communication with the surface, and which may be carried 
by the diver or suspended at any required depth, and will, by means of 
its reflector, cast its light many feet horizontally through the deepest 
water. This is a great auxiliary to the submarine workman, enabling 
him to inspect wrecks, examine and repair the copper and bottoms of 
vessels, and generally to see what he is doing. 

" The apparatus which Ave have described has already been used by 
the company, in many instances with great success. On the occasion of 
the first wrecking cruise of the company's vessel, the Saxon, from Xew 
York, the buoys were attached to a sunken vessel of two hundred tons 
in between four and five hours, and on their being inflated the vessel 
was raised to the surface in five minutes. The steamship Coffee, a 
blockade-runner, which was submerged in twenty-four feet water, was the 
next vessel raised by the aid of the apparatus, and among those which 
have since been lifted by the company are the schooner Tortugas, sunk in 
the harbor of Key West, Florida, and the W. E. Bartlett and the William 
Carleton, schooners sunk in Chesapeake bay: and a large quantity of 
valuable cargo was also raised from the brig William Edwards, a vessel 
which was sunk by a collision with the steamer Ariadne about eight 
and a half miles out to sea and thirty -five miles south of Sandy Hook. 
in seventy-five feet water. The company is now also perfecting a system 
for lifting and conveying vessels over shoals and bars, the draught of the 
vessels being reduced to the required extent by the application of buoys 
of a similar kind to those employed for raising sunken ships." 

DIVING APPARATUS OF ROUQUAYROL AND DENAYROUZE. 

Another form of submarine armor, differing chiefly from the foregoing 
in the provision made for the respiration of the divers, was exhibited 
by Messrs. Bouquayrol and Denayrouze, of Paris. A practical illustration 
was daily given, during the continuance of the Exposition, of the use of 
this apparatus, in a huge tank erected near the bank of the Seine, where 



SUBMARINE ARMOR REGULATION OF PRESSURE. 339 

one or two divers were constantly exhibiting to curious crowds the com- 
plete command which it enabled them to exercise over their movements 
in the water. This curious spectacle was commonly spoken of as " the 
human aquarium." 

The distinctive feature of the invention of these exhibitors consists in 
a contrivance called by them the " regulator." The design is to maintain, 
what is not done in any other form of diving armor, a constant equality 
of pressure between the interior and exterior of the chest. The diver 
carries with him, as in the case of the New York Submarine Company, 
his provision of compressed air for breathing in a reservoir secured 
to his back, but this air, instead of being admitted directly into the 
dress by means of a stop-cock operated by the diver himself, passes first 
through a chamber in which the pressure is automatically maintained 
exactly equal to that of the surrounding water. The construction of 
this regulator is very simple, and its operation is easily intelligible. 
Externally it appears to be a cylindrical box, about eight inches across, 
and two or three inches deep, placed upon the top of the air reservoir, 
with which it is firmly connected. The lid of this box is a circular 
metallic plate not quite so large in diameter as the box itself, but united 
to the circumference of the box by means of a flexible diaphragm. Thus, 
this disk has a certain freedom to rise and sink, while maintaining 
generally its position concentric with the cylinder, and closing the cavity 
against the admission of water or the escape of air. At the centre of 
this box in the bottom is a small valve opening upward, through which 
communication takes place when necessary with the chamber of com- 
pressed air. The valve is a spindle valve, with guides above and below, 
and is ordinarily kept closed by the upward pressure of the confined air 
beneath. From the centre of the movable lid above described descends 
a stem, which has guides like the spindle of the valve beneath, and 
which, as the lid descends, may strike upon the spindle and open the 
valve. The effect of the opening will be to allow the escape of a small 
portion of the confined air j and this, by raising the lid, will relieve the 
spindle, and permit the valve once more to close. The latitude of motion 
allowed to the lid is determined by two stops affixed to the central stem, 
and these stops admit of adjustment at the pleasure of the constructor, 
or of the person who is to use the apparatus. 

It is with the cavity of this regulator that the lungs of the diver are 
in communication. A tube leading from the regulator through the 
dress terminates in a mouth-piece which resembles the mouthpiece of 
a speaking trumpet closing over the lips, but is provided with two 
knobs or projections intended to be held between the teeth. The nos- 
trils are also closed by a compressing nose-piece provided with pads, so 
that the diver is compelled to exhale as well as to inhale through the 
mouth. As his lungs expand, the quantity of air in the regulator 
diminishes and the lid descends. The adjustments are such that when 
the inhalation is partially advanced — say to the extent of one-half — the 



340 PARIS UNIVERSAL EXPOSITION. 

valve of the reservoir is opened by the descent of the movable disk, and 
a quantity of air escapes sufficient for the completion of the inhalation. 
In exhaling, the air is driven back through the same tube into the regu- 
lator again, until the movement of the disk is arrested by the stop 
fixed on the stem for that purpose, and the remainder of the breath 
exhaled escapes through a valve attached to the tube. This valve is of 
a very simple kind. It consists of two thin sheets or ribbons of rubber 
cemented together at their longitudinal edges, but open at their extremi- 
ties. One extremity is fixed to the orifice of escape ; the other is free in 
the water. The two sheets are kept firmly closed by the external 
pressure until the regulator ceases to admit more air, and they then 
open freely to permit the excess to escape. 

The partial return of the air to the regulator is a measure of economy, 
and is attended with no disadvantage, since air can always be safely 
breathed a second time. It is known, in fact, that air which has once 
been inhaled contains somewhat less than five per cent of carbonic acid, 
and, after a second inhalation, about ten per cent. If we suppose the 
regulator to contain originally one hundred and fifty cubic inches of air 
at the ordinary atmospheric pressure, and that a man requires on an 
average thirty cubic inches at each inhalation, then, provided the stops 
are so adjusted that the diver returns one-half of this, or fifteen cubic 
inches, to the regulator at each exhalation, there will be, in the first 
instance, three-quarters of a cubic inch of carbonic acid returned, to be 
mingled with one hundred and forty-nine of pure air. At each succes- 
sive exhalation the proportion will be increased, but, under the circum- 
stances supposed, the maximum of impurity reached can never exceed 
five per cent. Supposing the air in the regulator to be of greater 
density, the ratio of maximum impurity will be proportionally less : 
since the mass of air received into the lungs will be greater under a 
given bulk, while the amount of carbonic acid generated will not be cor- 
respondingly increased. It would be quite safe, therefore, to adjust the 
stops for great depths in such a manner as to permit a larger portion of 
the air than one-half to be returned to the regulator. It has indeed been 
experimentally ascertained that a man in a diving-bell, in five or six 
fathoms of water, will be able, after a full inhalation, to hold his breath 
twice as long without inconvenience as he can in the atmosphere above 
the surface. This is intelligible when we consider that, at the depth 
supposed, the lungs contain, under the same bulk, twice the usual 
quantity of air. 

When it is stated that the regulator furnishes air to the lungs at a 
pressure equal to that of the water in which it is immersed, it will be 
understood of course that there is a difference too small to be of any 
practical importance, occasioned by the resistance to opening of the 
little valve communicating with the reservoir. The amount of this dif- 
ference may be calculated, when the diameter of the valve and the interior 
diameter of the reservoir are oiven. As there are two sizes of the 



PRESSURE WITHIN AND WITHOUT THE REGULATOR. 341 

apparatus employed, in one of which, designed for moderate depths, 
the pressure of the confined air is maintained, by means of a com- 
pression pump in a boat at the surface, at about one atmosphere 
only above that of the water at the diver's depth, the dimensions 
given to this are less, and the valve is made larger, than in the 
case of the other, which is called the high-pressure apparatus. A 
general expression may be found, however, for the difference of pressure 
within and without the regulator, which will apply to either case. Let 
D represent the interior diameter of the regulator, and d that of the 
valve. Put P for the downward pressure per square inch acting upon 
the regulator at the moment when the valve yields to the force exerted 
on the spindle, and p for the pressure per square inch exerted by the 
confined air in the reservoir. Put, finally, p' for the pressure per square 
inch of the air in the regulator. We wish to obtain an expression for 
the difference P — p' . 

The total downward pressure upon the surface of the movable disk is 
equal to JttPD 2 . 

The total upward pressure on the same surface is J-yD 2 . 

The upward pressure on the valve is \-pd?. 

And the downward pressure on the same is \-p'd 2 . 

On supposition of equilibrium, the sum of the pressures in opposite 
directions must be equal. 

Whence., 

or, (P_2y)D 2 =(j>— i)i)d\ 



And P— -p' = ( p —p' \j- z 



This being the condition of equilibrium, the slightest diminution of pj 
produced by the act of inhalation, will cause the valve to open. 

When the low-pressure apparatus is used, p — p' may be taken at about 
one atmosphere. Assuming the depth to be six fathoms, the pressure 
(in sea water) will be sixteen pounds to the square inch, to which must be 
added fifteen X30unds for the natural atmosphere, and, to be strictly accu- 
rate, the weight of the movable disk ; but this may be thrown out of the 
account as unimportant. In this apparatus D=200 millimetres, and 
d=l millimetres. 

Whence, 

P ^'= 15 2^= 15 iijlo= - 018375 ' 
or less than the fiftieth part of a pound per square inch. The difference 
of pressure within and without the regulator, that is to say, in the lungs 
and on the chest, would correspond to a difference in the barometric 
column not so great as four one-hundredths of an inch. 

In the high-pressure apparatus, the value of D is 300, and that of d y 
3J. At the same time, the pressure in the reservoir, p, is carried up as 
high as forty atmospheres, while^'is dependent on the depth of immersion. 



342 PARIS UNIVERSAL EXPOSITION. 

The reservoir in this case is not connected with the pump above, but the 
diver continues below until he finds his supply to be nearly exhausted, 
and then returns to the surface to replenish his stock. Whatever the 
depth to which he intends to go, he must begin drawing his breath from 
the reservoir from the moment of first immersion ; and hence, P — p' will 
have a value which is maximum at the surface, and which diminishes as 
he descends. The most unfavorable supposition will therefore be to make 
p— p'=39 atmospheres =585 pounds per square inch. 
Whence, 

-»~3.5 2 
300 2 



P—y =585^=0.0796, 



or about two twenty-fifths of a pound per square inch, which is about 
four times as great as in the former case, but still insignificant. 

Under the largest variation of conditions, therefore, this apparatus 
furnishes the diver with air for respiration at a pressure corresponding 
exactly with the depth of his immersion, and thus effectually removes 
one of the greatest disadvantages attending his difficult labor. 

The inventors of this apparatus have made no special provision of 
buoys to enable the diver to raise himself in the water, but the dress 
itself is made to serve the purpose of a buoy, air being admitted into it 
from the reservoir at pleasure. The diver can, therefore, at any moment, 
rise to the surface with the greatest facility. 

The capacity of the largest high-pressure reservoir is thirty-five litres, 
or 2,135 cubic inches. Filled with air compressed to forty atmospheres, 
it contains a quantity equivalent to 85,400 cubic inches at the ordinary 
atmospheric pressure, and this will suffice for the respiration of a single 
person for from four to six hours. 

The depth to which a diver can descend is limited by the exhausting- 
effect of the increasing pressure of the water upon his limbs and indeed 
upon his whole person. For whether the dress is maintained out of con- 
tact with his body, by internal armor plates "or frames, or not, there must 
always be a pressure of air within the dress equivalent to the water pres- 
sure without, or the consequences will be very serious. The Catalonian 
coral divers descend thirty-eight or forty metres, and are thus exposed to 
a pressure of four atmospheres in addition to the natural atmosphere, or 
five in all; but they scarcely remain more than twenty minutes at this 
extreme depth. Lieutenant Denayrouze is of opinion that a practiced diver 
diver, with his regulator, may descend at least fifty metres, going down 
and coming up slowly. The effects of pressure are much more endurable 
when the increase is gradual than when it is sudden ; and it is observed 
that the removal of heavy pressure, as in case of a very rapid ascent, is 
attended with sensations more disagreeable than attend its increase. 
The experienced diver will therefore rise from great depths very delib- 
erately, at the rate at first of only a metre or two a minute. By the 
proper management of the air admitted for buoyancy he can regulate 
his rate very accurately. 



APPLICATIONS OF SUBMARINE APPARATUS. 343 

A peculiar form of air-pump is employed by these inventors for charg- 
ing their reservoirs with compressed air. The barrels, instead of the pis- 
tons, are movable, the former being inverted relatively to the usual 
arrangement and attached by their closed extremities to the working- 
lever. The packing is of dished leather, and water is thrown in, in small 
quantity, at every stroke of the pump ; so that the piston is always cov- 
ered with a liquid stratum, and all leakage of air is effectually prevented. 
By an ingenious combination of levers, four pumps are simultaneously 
worked, each having the same length of stroke, but not the same cross 
section. The air is received, at a pressure of one atmosphere, by the 
largest of these, and transferred to the second under a pressure of three 
and a half atmospheres. From this it passes to the third, with a pressure 
increased to six; from the third to the fourth with the higher pressure of 
sixteen ; and from the fourth to the reservoir, at the desired final pressure 
of forty. The water introduced into the several cylinders has the effect 
to absorb a great part of the heat of compression, so that (it is stated) 
the fourth cylinder is always as cool as the first. 

The principal use for which this apparatus was originally designed is 
stated by the inventors to have been to facilitate the cleansing of the 
bottoms of vessels, while at sea, of the barnacles and sea-weed which 
constantly accumulate upon them, and which greatly impair their sailing 
qualities. It is said to have resulted from an examination of the logs of 
the armor-plated steam vessels of the French navy, that these vessels lose 
about two knots in speed in the course of a year while at sea, in conse- 
quence of such accumulations. This deterioration involves an increased 
expenditure of fuel, and may, in actual service, be the occasion of dis- 
advantages still more considerable. By actual experiment it has been 
found that with a moderate amount of labor periodically expended by one 
or two divers, the ship's bottom may be kept entirely free from these 
obstructions. 

The arrangements by means of which the divers are enabled to gain 
access to the surface to be cleansed are very simple. A rope ladder with 
wooden rounds is carried under the hull, and secured on deck at both 
ends. The diver descends this ladder, carrying with him his implements, 
and also a kind of seat or step furnished with hooks to be attached to 
the ladder at the point where he commences operations. For the parts 
which, on account of the curvature of the vessel, or the neighborhood of 
the keel, he is unable to reach in tbis way, he takes advantage of his 
power to rise in the water by inflating his dress, and thus ascends into 
these spaces and lays himself alongside of the surface on which he is to 
operate. 

Several commissions have been appointed by the French, British, 
Italian, and Dutch governments, to experiment and report on the merits 
of this apparatus, and the reports have been favorable in every case. 
The apparatus has therefore been recommended for adoption in the navies 
of all those nations. 



344 PARIS UNIVERSAL EXPOSITION. 

II.— LIFE-SAYIXG KESPIBATORY APPAKATUS. 

An apparatus somewhat resembling the diver's dress, but designed to 
enable firemen or others to enter houses filled with smoke, carbonic acid, 
or other deleterious gases, was exhibited on the bank of the Seine, and 
also at the island of Billancourt, by Mr. A. Galibert, of Paris. It con- 
sists of a helmet and mask, protecting the face and eves, and of a large 
reservoir of air, constructed of flexible materials, as, for example, leather 
or India-rubber cloth, containing a sufficient supply for the respiration of 
an individual for fifteen or twenty minutes at a time. This is strapped 
to the back of the person, while a tube proceeding from it conveys 
the air to the wearer's mouth. The mouth-piece resembles that of the 
diving apparatus of Messrs. Kouquayrol and Denayroirze, being held in 
like manner by the teeth of the wearer. The nostrils are also closed by 
means of a piece like that described as belonging to the diving dress 
just mentioned. 

The weight of the reservoir is trivial, not exceeding a kilogram, and 
the price of the whole apparatus is but one hundred and twenty-five 
francs. It is not necessary to insist on the usefulness of a contrivance 
of this kind. It has been successfully employed on very many occasions 
of danger, and has been the means of saving many lives. Its usefulness 
is by no means confined to the case of burning buildings. The foul air 
of wells, vats, mines, sewers, &c, is the occasion of the loss of many 
lives annually, and frequently the number of victims is increased by the 
efforts which are made to save the first who are asphyxiated. In every 
such case, a person armed with the respiratory apparatus may venture, 
without the slightest inconvenience, into the midst of the noxious fumes, 
and may in general withdraw the sufferers in time for their resuscitation. 

The dress may be put on in half a minute, and no longer time is neces- 
sary to inflate the reservoir. Should it be necessary to extend the time 
of use beyond that which the supply allows, the reservoir may be very 
quickly discharged and reinitiated. The time when it is proper to renew 
the supply will be indicated by the increasing rapidity of the respiration, 
as the air is returned to the reservoir on each exhalation, and the rate 
of breathing is the measure of its growing impurity. 

Numerous experiments on the use of this apparatus have been made 
in presence of commissions appointed by the board of health of Paris. 
by the minister of marine and the minister of public works of the 
French government, and by other authorities; and in consequence of 
the reports made upon the observed results, it has been introduced into 
the French navy, and into other branches of the public service of France. 
In the course of one of the series of experiments above mentioned, a 
member of the commission himself put on the dress and entered in per- 
son into a chamber which had been so thoroughly filled with smoke, 
carbonic acid, and other noxious gases, by burning in it damp straw, 
that it was almost impossible for any one to remain even in the adjoin- 



LIFE-SAVING RESPIRATORY APPARATUS. 345 

ing apartment near the door communicating' between the two, though 
the door was closed. He experienced not the slightest inconvenience 
from the experiment. 

The simplicity and cheapness of this apparatus, and the complete 
immunity which it secures to the wearer from the effects of noxious 
gases under any circumstances, would seem to make it an almost indis- 
pensable addition to the resources of any properly organized lire depart- 
ment, and to recommend it especially to navigators, who by its means 
may often be able to check a conflagration occurring in the hold of a 
vessel, or between decks, which might otherwise soon become uncon- 
trollable. 



CHAPTER XL 

IMPROVEMENTS IN THE APPLICATION OF HEAT. 

the economical transportation of heat— marval's heating apparatus— its 
application in baking and in other industries— slemenfe's regenerating gas 
Furnace— Its use in the production of glass — Hoffman's annular brick 

FURNACE. 

I.— TEANSPOBTATIOX OF HEAT. 

The economical transportation of heat from a furnace to the point of 
application is a problem of much interest. In the heating of dwellings 
the object is accomplished more advantageously perhaps by means of steam 
than in any other way. This method offers at once the combined advan- 
tages of economy, uniformity, healthfulness, and neatness. But steam as 
a carrier of heat is limited to a temperature much below what is required 
for many processes of industry, though this is not by any means true 
for all. In the chemical arts steam may often be thus advantageously 
employed, and this is likewise the case in many culinary operations, 
especially when such are conducted on a large scale. But there are 
some even among these for which it is not sufficient. The process of 
baking bread, for example, requires a temperature of five or six hundred 
degrees Fahrenheit; and this has heretofore been obtained only by the 
direct action of fire upon the walls of the oven, applied either internally 
before baking, or externally while the baking is going on. This very 
uncertain, irregular, and uneconomical mode of applying heat for such 
purposes has been effectually superseded by a recent invention of Mr. 
Joly de Marval, of Paris, in which a current of water confined in a tube 
is made the medium of transporting a heat of the most regular character 
from the source to the point of application, and of any temperature from 
two hundred to eight hundred or nine hundred degrees. 

MARVAL'S HEATING APPARATUS. 

The heat is imparted to the water by conducting the tube containing 
it, coiled into the form of a spiral, through the furnace itself, where the 
fire is in immediate contact with its surface. It is transported to the 
point of application by taking advantage of the mobility of fluids, and 
of their expansibility under the influence of heat. The furnace must 
be at a lower level than the space to be heated, and the tube at this latter 
point must be developed into other coils or zigzags, so as to present a 
large amount of radiating surface. Further, in order that the transpor- 



HEATING APPARATUS —APPLICATION TO BAKING. 



Al 



tation of heat may go on continuously, the tube itself must be continuous 
or endless, so that as the water heated by the furnace rises on one side, 
that which has more or less wholly given up its heat may descend on the 
other. It is true that water raised in confinement to temperatures such 
as have just been mentioned, exerts a tremendous pressure upon the 
walls of the containing vessel; but it is also true that the danger of 
explosion from high pressure is less as the diameter of the vessel is 
less, and that small iron tubes of given thickness will bear a pressure 
which when stated seems almost incredible. Mr. de Marval has tested 
his tubes to seven hundred atmospheres, that is to say, to more than ten 
thousand pounds to the square inch. He subjects them ordinarily to a 
pressure not exceeding two hundred atmospheres, or three thousand 
pounds to the square inch. 

The tubes are about Fig. 81. 

three-quarters of an inch 
(eighteen millimetres, in 
diameter internally) and 
about twice as large (thir- 
ty-eight millimetres) ex- 
ternally. 

The manner of adapt- 
ing this plan of heating 
to a large oven for the 
baking of bread may be 
understood by reference 
to the accompanying fig- 
ures. Fig. 81 is a section 
in elevation of the oven 
and furnace ; and Fig. 82 
is a view in plan. The 
spiral in the furnace is 
shown at A directly over 
the bars of the grate. It 
ascends by the tube o, 
which is external to the 
furnace, and is protected 
by a sheath of sheet iron, 
makes a bend at H, where 
is attached the COlltri- Marval's Heating Apparatus— section, 

vance D, (to be presently explained,) and then forms a flat spiral B, as 
shown in Fig. 82, in the roof of the oven, where the coils are distant from 
each other little more than t \e diameter of the tube. From this spiral 
it is carried again outside of the masonry to the point d, seen in both 
figures ; then it descends and re-enters to form a third spiral ee, under 
the floor of the oven, which last is formed of thin tiles which are soon 
heated through. Thence it descends after again passing out through 




348 



PARIS UNIVERSAL EXPOSITION. 




the wall by the straight tube e', which connects and is continuous with 
the original spiral A, at the bottom. This tube e' is not indicated in 
Fig. 82. Fig. 82. M. de Marval causes this 

portion of the tube to pass 
through the water tank G, for 
the purpose of keeping up a con- 
stant supply of hot water for gen- 
eral uses. 

It will be understood that the 
expansion of water with increase 
of temperature is much greater 
than that of iron, and consequent- 
ly that if the tube is absolutely 
full of water, the pressure which 
it is capable of exerting by its 
expansion as a liquid will be a 
great deal greater than that which 
would belong to steam formed at 
an equal temperature. It is neces- 
sary to provide against this; and 
such a provision would at first 
thought seem to be easilv and 
Marval's Heating Apparatus-plan. effectually secured by leaving a 

small portion of the tube to contain air only. But inasmuch as the circu- 
lation of the liquid is the condition indispensable to the transportation of 
the heat, and as this circulation is determined only by the different densi- 
ties of the water in the ascending and descending branches, it is evident 
that by admitting an air space or a steam space we should effectually arrest 
the operation of the contrivance. To provide against this, the attach- 
ment shown at D is added. This is a cylinder somewhat larger in diam- 
eter than the tube, and communicating with the latter at the bend H. 
Within the cylinder is a piston closely fitting by metallic packing and 
having a piston rod which is hollow and forms a communication between 
the cavity below the piston and the outward air. This piston rod is also 
very closely packed, so that the space within the cylinder is filled with 
air which cannot escape and which may be compressed to any degree. 
At the point &, in both figures, is seen the extremity of a tube which 
communicates with the lower spiral at the lowest point. It is through 
this tube b that the apparatus is charged with water. The piston in D 
being depressed to the bottom of the cylinder, and its rod being open to 
the air, the water rises regularly from the lowest point of the system to 
the highest, driving out the air before it, filling all the tube, and finally 
appearing in the interior of the hollow piston rod, which is the highest 
point of all. This rod is then firmly closed by screwing on an air-tight 
cap, and the tube b is secured in like manner. 

The joinings of the tubes which form the several spirals are very 



marval's heating apparatus. 349 

strongly secured. The extremities of the tubes to be joined are, in tact, 
cut with screw threads turning in opposite directions, one being a right- 
handed and the other a left-handed screw. A single nut, correspondingly 
cut in its two opposite halves, brings the tube ends together by one 
operation, a ring of copper being interposed to form a washer. After 
forcing the nut hard up, guard screws are driven firmly up against it on 
both sides, with an interposition of white lead or ottier drying cement. 

Having thus described the general construction of this apparatus — of 
which an example on a large scale was in continual operation at the 
Exposition, and which was daily open for inspection at the bread-baking 
establishment of the inventor in Paris — its value, considered as an addi- 
tion to the resources of this important industry, and not of this one alone, 
but of very many others to which it is equally applicable, may be best 
shown by presenting the substance of some extracts from a report made 
on the subject by Mr. Babinet, of the French Academy of Sciences. 

"In studying this admirable apparatus," he remarks, "I recognize the 
fact that it takes up the heat of the fuel in the furnace with a simplicity 
and an efficaciousness without parallel, and conveys it at will to different 
places, making it subserve there various uses of the greatest importance. 
A long examination of the contrivance convinces me that the construc- 
tion of its parts leaves nothing to be desired in regard to security, effi- 
cacy, and perfect performance, while it is nevertheless manifest that, in 
spite of the simplicity of the process, these results have only been obtained 
after long and expensive experiments which bring to mind those which 
preceded the creation of the locomotive. Everybody is acquainted with 
the caloriferes and tubes full of water which carry slowly a moderate 
heat to a distance more or less removed from the furnace. Perkins 
obtained much more marked effects of the same kind, but without regu- 
larity of law ; and I do not hesitate to affirm that the Messrs. Joly de 
Marval, in deriving heat from a furnace, ingenious in itself, and by means 
of tubes in which there is established an energetic circulation perfectly 
regulated, have made a fundamental discovery." 

After remarking on some particulars of the construction, and observ- 
ing that the durability of the tubes is such that they can be relied on 
for years without the necessity of repairs, he continues : " A furnace of 
several cubic metres capacity can be kept constantly heated to 300° C, 
(570° F,) and above, for twenty -four hours, at an expense for fuel of about 
five francs. I have inspected the interior of the oven, and a batch of 
large loaves was baked in my presence in half an hour. All who exam- 
ined the loaves were satisfied that they were perfectly done through, 
having a golden and very inviting crust, and a crumb entirely uniform, 
being also without burns or knots. As I say all this from my own ob- 
servation, I can affirm that into the high estimate put upon the perform- 
ance of these ovens, (of which one at the Exposition supplies to the civil 
and military administration, daily, ten thousand small cakes and loaves,) 
there enters neither exaggeration nor partiality. The interior of the 



350 PARIS UNIVERSAL EXPOSITION. 

oven is constantly neat, and the loaves leave it in a condition as nice as 
possible j while in ordinary ovens the waste amounts to one loaf in 
twenty. 

" The endless tube, or canal, in which the superheated water circu- 
lates, may pass at need through a boiler filled with water. It creates 
in such a boiler a development of vapor truly astonishing, capable of 
giving without any additional expense a force of one or two horse-power, 
which can be employed to operate a kneading machine, or for any other 
purpose. The furnace occupies but a very small space, and the use of 
coal dispenses with the immense and highly dangerous accumulations of 
fire-wood required to maintain ordinary bakeries. 

" An important additional consideration, which is to be further taken 
into account, is the absence of the deleterious influences to which the 
operatives employed to remove from the ovens in general use the incan- 
descent embers and other results of combustion are exposed $ and which 
are exerted by the excessive heat and the oxides and other gaseous com- 
pounds of carbon which are exhaled from the imperfectly burned wood. 
It is rare that these workmen are not forced to abandon their employ- 
ment at forty years of age ; and if the establishment is large, the neces- 
sity of keeping the windows open is an additional cause of insalubrity. 
I think that in our age which, in a spirit of solaudible humanity, occupies 
itself so much with the public health, these considerations militate greatly 
in favor of an apparatus so entirely hygienic. 

u Messrs. Joly de Marval, with reason, claim for their invention an appli- 
cability to plaster-kilns, to distilleries, to refineries, to field-ovens, to 
pumps, generators of steam for steam-engines, and to all other forms of 
industrial apparatus in which it is desired to maintain a regular heat 
anywhere from 50° to 400° C, (from 120° to 750° F.) In a word, this 
heat is entirely uniform and inoffensive, and is susceptible of application 
to all exigencies. It has cost the inventors many years of scientific 
industrial labors. They have happily succeeded in overcoming all prac- 
tical difficulties. Besting upon a basis of sure calculation, they perfectly 
master water superheated to four or five hundred degrees, (750° to 
930° F.) 

" What is to me the most seducing part of their labor. I find in the 
tables which give the relation between the temperature and the elastic 
force of vapor, at degrees of heat which had not been hitherto calculated. 
To this end they have employed a special form of manometer, which the 
most simple workman can easily consult in order to maintain the proper 
operation of the apparatus. I think it may be safely affirmed that in- 
dustry has been presented in this invention with an element of real 
importance, and one which will in the future be more and more appreci- 
ated." 

One remark only remains to be made. As the compensator is added 
to the contrivance to permit the expansion of the water with the 
rising of the temperature, it is found practicable, in case of necessity. 



SIEMENS'S REGENERATING FURNACE. 351 

to make the apparatus to a certain extent self-regulating, by forming 
such connect ious with the piston-rod of the compensator as to cause a 
jet of water to be thrown into the furnace whenever the heat becomes 
excessive. The same piston-rod may, also, instead of this, be connected 
with a signal bell, or other indicator of the state of the apparatus, which 
may serve to call the attention of the attendant to the necessity of reg- 
ulating the fire. 

H.— FURNACES. 

SIEMENS'S REGENERATING FURNACE. 

The most valuable of all the improvements in the arts of metallurgy, 
so far as it relates to the economical and effectual application of heat, 
is that which is presented in the regenerative gas furnace of Mr. Siemens, 
of London. This was exhibited in model in the Exposition, and was 
rewarded with the highest honor in the power of the jury to bestow, the 
grand prix. As the invention is one of the most important of recent in- 
ventions in the industrial arts, it comes properly under review in this 
place, although it belongs to the committee on metallurgy to treat in 
detail of its uses and its economical value. In the London journal En- 
gineering, for June 21, 1867, is contained an account of this furnace, in 
which its theory and general construction are so clearly explained as to 
seem to the present reporter preferable to any original description of his 
own. It is therefore subjoined. 1 The writer observes : 

" There are two distinct principles embodied in the Siemens furnace, 
viz., the application of gaseous fuel and the regeneration of heat by 
means of piles of brick alternately passed over by the waste gases and 
by the gases entering the furnace before their combustion. Each of these 
principles is an important invention in itself, and capable of a useful 
application in practice without the other ; still, the advantages of the 
combination of both principles as now existing in the Siemens furnace 
have given to the whole its great value and excellent economic results. 

" The gaseous fuel is produced in a special chamber, called the ' gas 
producer,' or ' generator.' The latter name, however, is objectionable, 
on account of its similarity with the name ' regenerator ' given to the 
other vital part of the furnace, the two names having no correspondence 
of meaning. The gas producer is a brick chamber about six feet wide 
by twelve feet long, with its front wall inclined at an angle of 45° to 60°, 
according to the nature of the fuel used. The inclined plane is solid 
about half way down, and below this it is constructed as a grate with 
horizontal bars. The openings for introducing the coal into the gas pro- 
ducer are on the top or roof of this chamber, and the air which enters 
through the grate effects the combustion of the coal at the lowest points 
of the chamber. The products of this combustion rise and are decom- 

1 A short description of this furnace, accompanied by drawings, will also be found in the 
report of Commissioner Hewitt upon iron and steel, &c. 



352 PARIS UNIVERSAL EXPOSITION. 

posed by the superposed strata ; they are, moreover, mixed with a quan- 
tity of steam which is drawn in through the grate from a constant sup- 
ply of water maintained underneath the latter. The steam in contact 
with the incandescent coal also decomposes and produces hydrogen and 
carbonic oxide gas, which are mixed with the gases produced by the coal 
direct. The whole volume of these gases is then conducted to the fur- 
nace itself by means of wrought-iron pipes. The gases enter one of the 
regenerators. The regenerators are chambers packed with fire-bricks, 
which are built up in walls with interstices and air spaces between them, 
allowing of a free passage of gas round each single brick. Each regen- 
erator consists of two adjoining chambers of this kind, with air pas- 
sages parallel to each other, one passage destined for the gaseous fuel, 
and the other for the supply of atmospheric air required for combus- 
tion. Each furnace has two such regenerators, and a set of valves 
is provided in the main passages, or flues, which permits of directing the 
gases from the producer to the bottom of either of the two regenerators. 
The gases, after passing one regenerator, arrive at the furnace, where 
they are mixed with' the air drawn in at the same time, and produce a 
flame of great heat and intensity within the body of the furnace itself. 
They then pass, after combustion, into the second regenerator, which 
forms a set of down flues for the waste gases, and ultimately leads them 
off into a common chimney. On their way from the furnace to the chim- 
ney, the heated products of combustion raise the temperature of the 
fire-bricks over which they pass to a very high degree, and the gases are 
cooled more and more the further they proceed through the regenerator. 
After a certain time, the fire-bricks close to the furnace obtain a tem- 
perature almost equal to that of the furnace itself, and a gradually dimin- 
ishing temperature is arrived at in the bricks of the regenerator propor- 
tionate to their distance from the furnace. At this moment the attend- 
ant, by reversing the different valves of the furnace, opens this heated 
regenerator for the entrance of the gaseous fuel and atmospheric air, at 
the same time connecting the other regenerator with the chimney for 
taking off the products of combustion. The entire current of gases 
through the furnace is thus reversed. The cold air from the atmosphere, 
and the comparatively cold gases from the producer, in passing over 
bricks of gradually increasing temperature as they approach the furnace, 
become intensely heated, and when they are mixed in the furnace itself, 
enter into combustion under the most favorable circumstances for the 
production of an intense heat. The principle of this so-called regenera- 
tion of heat, therefore, consists in storing up the waste heat in one set 
of fire-bricks, and afterwards making use of that heat for elevating the 
temperature of the fresh gases introduced for combustion. The action 
of these regenerators is so perfect that, with a temperature of somewhat 
about 4000° in the furnace, there is no more than about 300- to be felt 
at the base of the chimney, the escaping gases having a temperature no 
greater than is absolutely required for maintaining the draught. The sup- 



SIEMENS'S REGENERATING FURNACE. 353 

ply of air from the atmosphere, as required for combustion, is entirely 
due to the draught of the chimney, but the supply of combustible gases 
is made independent of it on account of the inconvenience and danger 
which would arise from a gas pressure below that of the atmosphere in 
the gas mains or pipes. The consequence of such an underpressure or 
partial vacuum in the gas-pipes would be the influx of air through all 
leaks and fissures in the joints of the gas-pipes, and this would lead 
to a premature mixture of the air with all the combustible gases, with 
a waste of fuel, and, in some cases, would even cause dangerous explo- 
sions. It is, therefore, desirable to maintain in the gas-pipes a pressure 
slightly exceeding that of the atmosphere. In the majority of cases this 
effect is produced by placing the gas producers at a considerably lower 
level than the furnace itself; the gases being at a temperature of 300° to 
400°, and consequently of less specific gravity than the outer atmo- 
sphere, are forced through the tubes by gravitation, and maintain a slight 
surplus of pressure, due to the difference of weight of the column of 
heated gases and of an atmospheric column of equal height. Wher- 
ever the placing of the gas producers at a lower level is impracticable, 
Mr. Siemens obtains the same result by sending the gases up a vertical 
pipe to a height of some twenty or thirty feet, and then through a hori- 
zontal pipe of considerable length for allowing the gases to cool in their 
passage, and from which they descend again through another vertical 
pipe. The gases in the down flue are colder than those in the upcast, 
and they therefore give the requisite difference of weight in the gaseous 
columns necessary for that purpose. Mr. Siemens has carried out this 
arrangement at his Model Steel Works, in Birmingham, and it works 
very successfully. In Sweden, Mr. Lundin has recently proposed and 
even patented an arrangement for cooling the gases in the flues of the 
Siemens furuace, by means of a spray of cold water injected among 
them. M. Lundin, by these means, at the same time effects a purifica- 
tion of the gases from solid matter carried along mechanically, and from 
certain gaseous combinations which are absorbed by water. These latter 
gases in some instances are sulphurous acid and other noxious sub- 
stances, and the purification therefore may, in some instances, and with 
certain kinds of fuel, become of great value to those who use the Siemens 
furnace. It is doubtful, however, whether Mr. Lundin's improvements 
can substantiate a valid patent, since Mr. Siemens has, in some of his 
specifications, described the cooling of his fuel gases by water, although, 
perhaps, not with the intention of washing and purifying these gases 
from mechanical and chemical admixtures. 

" This is the present state of this beautiful and important invention. It 
has supplied us with the power of maintaining an exactly regulated tem- 
perature in a furnace of any required size and shape; it has made us 
practically independent of the quality and nature of the fuel used for 
producing the required heat from the most moderate up to the very 
highest temperature. It has reduced the expenditure for fuel to a very 
23 i A 



354 PARIS UNIVERSAL EXPOSITION. 

great extent, and it has given us one of the greatest desiderata in so 
many metallurgical operations, viz: a clean furnace, free from ashes, dust, 
and dirt, and perfectly suitable for the working of the more refined and 
purified materials which modern industry has produced and is still con- 
stantly improving upon. We have further to name as an important 
feature of the Siemens furnace, the possibility afforded by it of changing 
the nature of the flame at will, by altering the relative proportion of air 
and gas admitted through the flues. A surplus of oxygen in the mix- 
ture will produce an oxidizing flame, and will give all the corresponding 
effects upon the materials exposed to its action. By the admission of a 
surplus of gas, on the contrary, the flame can be made of a reductive 
character, and used accordingly for deoxidation. In metallurgy, and 
particularly in the treatment of iron and steel, this is of the utmost 
importance. There are already several new modes of manufacturing 
steel direct from the pig iron, patented and practically carried out in 
France and in Germany, wherein the Siemens furnace is made use of as 
an indispensable condition for their success. The exhibition contains a 
collection of samples of very fine steel made by Mr. Berard's process. 
This is called ' acier a gazf and is made in a Siemens furnace direct 
from pig iron. Mr. Berard constructs a Siemens furnace with the bottom 
formed into two separate parts, each hollowed out like a dish, and with 
a bridge between them upon which the pigs introduced into the furnace 
receive a preliminary heating. The flame is maintained with a surplus of 
oxygen, and a quantity of pig iron is melted in one of the chambers or 
dishes. The oxidizing action of the flame decarburizes and refines the 
pig iron, and, after a certain time, a second quantity of pigs is thrown 
into the second dish and melted there. The flame is now reversed in 
its direction; the oxidizing flame is made to enter at the side Avhere the 
fresh pig iron is placed. In passing over this, and oxidizing the carbon, 
silicon, and other impurities in the iron, the flame loses its surplus oxy- 
gen, and becomes of a neutral or, at least, only slightly oxidizing char- 
acter. In this state it passes over the other bath of molten iron, now 
partly refined, and it continues to act upon the impurities without at- 
tacking the iron itself. At a certain moment this portion of iron is 
completely converted into steel, and that part of the furnace is then 
tapped so as to make room for a fresh charge of pigs in that place. After 
that, the current of gases is again reversed, the second bath now enter- 
ing into the position previously taken by the first, and so the process is 
carried on continuously with two portions of iron, one freshly introduced 
and acted upon by the oxidizing flame, the other partly converted into 
steel and exposed to the neutral flame passing away from the first. Mr. 
Berard states, that by protracting his process, and by adding spiegelei- 
sen, he can remove sulphur and phosphorus from the iron, and make 
steel from inferior pigs. Such statements, however, have been so fre- 
quently made by inventors, without having been borne out by facts in 
actual practice, that we must be cautious in accepting them. 



PRODUCTION OF STEEL AND GLASS IN SIEMENS's FURNACE. ,'355 

" Messrs. Emile and Pierre Martin, of Sireuil, have also commenced 
steel-making in a Siemens furnace. They melt a quantity of pig iron, 
and introduce wrought-iron scrap, puddled steel, or other malleable iron 
into the mass while exposed to the oxidizing influence of the flame. They 
have produced steel of excellent quality by this method, and are now 
about to introduce their process into several steel works in France. The 
great advantage obtained by them, and one which has not yet been 
arrived at by the Bessemer process, is the conversion of old iron rails 
and similar articles into steel. That this is a great desideratum — particu- 
larly at this present moment of transition of the permanent way from 
iron into steel — is well known, and attempts have been made by Mr. 
Bessemer, Mr. Adamson, and several others, to effect the same thing in 
the Bessemer converter. The first trials, although they proved the pos- 
sibility of converting old iron rails into steel in that manner, gave an 
unsatisfactory commercial result. It was found that the rails required 
to be heated to a white heat before being introduced into the converter, 
that no more than one-third of such rails could be added to the propor- 
tion of two-thirds of every graphitic pig iron, and, with all this, that there 
was a greater waste in the converter, and more " scull" in the ladle, than 
with pig iron. Messrs. Martin, on the contrary, are able to use a pro- 
portion up to two-thirds of old rails to one-third of pig iron ; they can 
manage the fusing very completely, and without excessive waste, and 
with a moderate consumption of fuel, advantages which are.all due to 
the Siemens furnace which they employ." 

The Siemens furnace was patented several years ago, but it seems at 
first to have been looked upon with some distrust and to have been 
received with hesitancy. Of its introduction, the writer above quoted 
remarks : 

"The first manufacturers to avail themselves of the new furnace 
were the glass-makers. The British plate glass works, at St. Helens, 
Messrs. Lloyd and Summerfield, of Birmingham, and Messrs. Chance 
Brothers, Birmingham, were, we believe, among the first who intro- 
duced the Siemens furnace in their works. For purposes of metallurgy, 
greater difficulties and prejudices had to be surmounted. Some of the 
steel-makers on the continent led the way. Mr. Mayr, of Leoben, in 
Styria, we understand to have been the first to introduce the new fur- 
nace for crucible-steel making, on a large scale. In this instance, the 
unfavorable position of the Styrian Iron Works in regard to the supply 
of mineral fuel, was the principal inducement to apply gas in the steel- 
melting furnace. The gas is made in Mr. Mayr's works, from lignite, 
which cannot be directly applied for melting steel, as the heat of it, 
when burnt on the grate, is not sufficient to produce the high tempera- 
ture required for this operation. Mr. Mayr erected ten gas furnaces, 
and they have proved a complete and perfect success, enabling him to 
make crucible cast-steel by means of the cheap and very inferior lignite 
which exists in his locality. 



o5G PARIS UNIVERSAL EXPOSITION. 

"For puddling iron and steel, the Siemens furnace was also first 
applied on the continent in localities where fuel is scarce, or of infe- 
rior quality, and of small heating power. In England the reheating of 
iron and steel blooms seems to have been among the first applications 
of the Siemens furnace. Messrs. James Russell and Sons, of Wednes- 
bury, the Elswick Works, and the Mersey Steel and Iron Works,were 
among the first licensees of Mr. Siemens. In Sheffield, Messrs. Bay- 
lor, Vickers and Co., Messrs. Thomas Firth and Son, and Messrs. Cam- 
mell and Co., took up the gas furnace for melting steel and for reheat- 
ing the blooms and forgings and within the last two years the Siemens 
furnace has been adopted in all the larger Bessemer steel works in the 
kingdom. Mr. Siemens has also erected a small experimenting steel 
works of his own in Birmingham, of which we gave a notice some time 
ago. In France the Siemens furnace is gaining ground with equal 
rapidity. The Imperial arsenal at Lorient, Messrs. Emile and Pierre 
Martin, in Sireuil, and several other steel makers, have had Siemens 
furnaces in successful operation for several years ; there are many more 
recently erected in other works, such as Messrs. Yerdier's steel works, 
at Firmini, and there are now twenty furnaces in course of erection under 
Mr. Siemens' s own superintendence at the Creuzot Works." 

A recent very important application of the Siemens furnace has been 
made in the crystal or flint glass works of St. Louis, in the department 
of the Moselle, France. In this case, a modification has been introduced 
by Mr. Didierjean, the director of the works, which has rendered it pos- 
sible to conduct the manufacture in'open crucibles, an important point 
which, nevertheless, it has been hitherto impossible to secure with any 
fuel but wood. At present, in this great establishment, which turns out 
daily sixteen tons of flint glass, and employs sixteen hundred workmen, 
and one hundred or one hundred and fifty artists, the Siemens furnaces 
are used with no fuel but coal, and the meltings take place in open 
crucibles. 

The disadvantage heretofore experienced in working in this manner, 
has been the liability of the metallic base of the glass to become discol- 
ored by contact with reducing gases. Xo expedient hitherto tried could 
remedy the evil; and hence, as a matter of necessity, the materials have 
been melted in retorts or in covered crucibles. The modification of form 
of the Siemens furnace which has removed this difficulty, is one by means 
of which the carbonic acid formed by the combustion is caused, in conse- 
quence of its superior specific gravity, to roll over the crucibles and to 
form a protecting cushion between them and the lighter, which are the 
reducing gases. The crucibles occupy the circumference of the floor of 
the furnace, the gases are introduced into the furnace through vertical 
passages opening nearer the middle. The reducing gases enter on the 
interior side and the oxygen on the exterior: when the flame reflected 
from the roof turns downward, it is prevented by the cushion of carbonic 
acid from touching the materials in the crucibles, which thus maintain 
all their purity and produce a crystal of the highest brilliancy. 



ANNULAR FURNACE FOR BURNING BRICK AND TERRA COTTA. 357 

The specific gravity of the crystal of St. Louis is 3.37 This great 
weight is due to the quantity of lead which, it contains; it much exceeds 
in this respect the crystal of Paris and its vicinity, and also that of 
England. This crystal refracts light much more powerfully and is much 
more brilliant in every respect than any other at present manufactured. 

HOFFMANN'S ANNULAR BRICK FURNACE. 

The annular furnace for burning brick, invented by Mr. Frederick 
Hoffmann, of Berlin, which presents one of the most admirable arrange- 
ments for promoting efficiency and economy ever introduced into any 
branch of industry, was exhibited in several beautiful models. This fur- 
nace has already come extensively into use in most European countries, 
and it is impossible to examine the principles of its construction, and to 
become acquainted with its mode of operation, without being satisfied that 
it is destined to supersede all other ovens, furnaces, or kilns, wherever 
brick-making is carried on as a manufacture, and not merely for some tem- 
porary and local purpose. It will require but a few words to explain the 
general plan on which this furnace is constructed. A large annular 
chamber, with proper openings at the sides to permit the introduction 
or withdrawal of the articles to be burned is constructed with a central 
chimney and with removable divisions for separating the annulus into 
different parts. If, now, we suppose the annulus to be filled with un- 
burnt bricks, and that heat is applied to one division, the smoke or hot air 
escaping from that division will be employed to dry the bricks in the 
next compartment before it finally escapes to the chimney. The com- 
partment thus dried will be the next one burnt, and the air required to 
maintain the combustion in the burning compartment will be made to 
enter through openings among the bricks last burned, whereby those 
bricks are rapidly cooled and the air by means of which the combustion 
is maintained is heated. The coal, instead of being burned on a com- 
mon grate, is introduced in the form of dust through small orifices pro- 
vided for the purpose, and closed with plugs all around the top of the 
annular kiln, and the fineness of this dust is so adjusted to the height of 
the oven that it is consumed by entering into combustion before it reaches 
the oven floor. Each compartment of bricks or other objects is thus burn t 
in its turn, and so the process goes on continuously, the waste heat of the 
burning compartment continually drying the compartment before it, and 
taking all the heat of the compartment behind through the medium of 
the heated air. The figure here presented illustrates the arrangement. 

The letters a a mark the circular vaulted furnace into which the bricks 
to be burnt are introduced through the doors b b. Flues or passages, 
c c, lead to the circular chamber or drum e e, surrounding the central 
chimney d. Valves of cast iron/ /, close at pleasure the orifices of the 
channels c c. Movable sluices g g, formed in the thickness of the divid- 
ing walls, enable the different radial chambers to communicate or stop 
communication between them ; li h are plugs through which the coal, in 



358 



PAEIS UNIVERSAL EXPOSITION. 



a state of powder, is introduced into the compartment undergoing cal- 
cination. In this furnace there are twelve compartments, of which only 
Fig. 83. two will be separated by the 

sluices, in one of which the 
new bricks will be in the act 
of being placed, and from the 
other the burnt bricks will 
be in the act of being with- 
drawn. The whole of the 
materials in the other com- 
partments will either be heat- 
ing the air entering to main- 
tain the combustion in the 
active part, or will be being 
heated by the hot air which 
passes off from the active 
part on its way to the chim- 
ney. The necessary changes 
in the direction of the cur- 
rents of air are made by rais- 
ing or lowering the valves, 
and the action of the furnace 
is thus rendered continuous, 
the materials being continu- 
ally fed into one compart- 
ment and withdrawn from 
the other. The advantages 

Huffman's Annular Brick Furnace. of this furnace lie in its great 

economy of fuel, amounting, it is said, to two-thirds of that usually con- 
sumed in common furnaces. There is also greater equability in the heat, 
and the articles are more gradually heated and more gradually cooled. 
There is no smoke generated, and the fuel is burnt while falling by 
gravity to the bottom of the furnace. Such furnaces are useful for 
roasting ores or cement, or for baking fine pottery, as well as for burn- 
ing bricks. 

Another advantage consists in the fact that the progress of the oper- 
ation may be easily inspected in all parts of the mass exposed to the heat 
while it is going on, and the degree of heat may be increased or dimin- 
ished at pleasure, preventing any danger of injury or loss from over- 
burning or from under-burning. 

These furnaces are likely to come largely into use in manufacturing 
ornamental terra cottas for house fronts, as in cornices, friezes and lin- 
tels, as well as for statues, vases, fountains, &c, to be used as rustic 
embellishments of landscape gardening. 

The statement of the inventor that the saving amounts to two- thirds 
in respect to fuel is confirmed by the results of experience in the use of 




ECONOMY OF HOFFMAN'S ANNULAR BRICK FURNACE. 359 

the Hoffmann furnaces in England. From these it appears that the 
saving is even greater than he claims. At the works of Mr. Betty, at 
Kensington, the following represents the comparative cost to the pro- 
prietor of brick per thousand, by the old and new methods of burning. 
These numbers are given in the Practical Mechanic's Journal of October 
1, 1865, by the superintendent of the works: 

Cost of -production of one thousand brick. 

Old brick-kilns. Hoffmann furnaces. 

For wages £0 Is. 6d, £0 Os. M. 

For coal, 10 cwt 7 10£ 2 cwt. 1 7 

For loss 1 

Total 10 U =$2 50 2 1 =$0 50 



Giving a ratio of economy as one to five. 

The following is the result of observations made at Durham by Mr. 
G. Furness : 

Comparative cost of production of 222,000 brick in old-fashioned Scotch 
brick-kilns and in Hoffmann's furnaces. 

Scotch furnaces— 17 tons 14 cwt., at 15s. the ton £59 15s. 5tf,=$289 29 

Hoffmann's furnaces — 27 tons 12 cwt., at 12s. 6d. 
the ton 17 5 = 84 70 



Difference 42 10 5 =204 59 



Giving a ratio of economy as one to three and four-tenths. 

Such results as this, added to the very superior quality of the brick 
obtained by this process, are sufficient to insure the general adoption by 
manufacturers of this exceedingly important improvement. Already, 
more than four hundred Hoffmann furnaces are in operation in Ger- 
many, and about thirty in England. A single establishment in Vienna, 
that of Mr. Henry Drasche, employs nineteen of them, having each a 
capacity to produce eight million of brick per annum. Mr. Drasche 
employs forty-five hundred workmen, and turns out annually one hun- 
dred and ninety-eight milllion of brick ; but, besides this, he produces 
a vast multitude of objects of ornament in terra cotta, designed for the 
decoration of buildings and grounds — a class of works very favorite in 
Austria, both for their beauty and for their cheapness. 

Mr. Drasche exhibited one of the most attractive collections of bas 
reliefs, statues, vases, architectural and other ornaments in the Exposi- 
tion; all of them formed in terra cotta. His display was as remarkable 
for the great number of beautiful objects which it contained as for the 
taste with which they had been designed. They were bought up by 



360 PARIS UNIVERSAL EXPOSITION. 

visitors with eagerness, and only a few weeks had elapsed after the open- 
ing of the Exhibition before nearly every object in the whole collection 
bore the mark which, in all quarters, grew more and more familiar every 
day, " sold." All these beautiful productions were baked in the Hoff- 
mann furnaces of Mr. Drasche's establishment. 



CHAPTER XII. 
ARTIFICIAL PRODUCTION OF COLD. 

General observations— Useful applications of cold— Freezing mixtures — 
Reduction of temperature by evaporation — Artificial production of ice- 
Carre's SULPHURIC ACID FREEZING APPARATUS— CARRE'S AMMONIACAL FREEZING 

apparatus— Cost of ice produced in this form of apparatus— Carre's con- 
tinuous FREEZING APPARATUS — USEFUL APPLICATION OF REFRIGERATING APPARA- 
TUS— Twining's American ice machine— Economy of production of ice by 

TWINING'S APPARATUS. 

I.—GENERAL OBSEKVATIONS. 

The importance to the arts of industry and to the promotion of human 
comfort of being able to control temperatures, as, for instance, in an 
apparatus, in an apartment, or, in fact, in any given space, large or 
small, is too obvious to need illustration. As respects the higher tem- 
peratures, it may, indeed, be said that without the power to create such 
temperatures artificially, and to carry them to a degree of elevation 
immensely superior to any which nature, under ordinary circumstances, 
anywhere presents over the habitable surface of the earth, the industrial 
arts as now understood could not exist, and civilization itself would be 
impossible. 

The useful applications of cold are less numerous and less obvious. In 
most climates, in fact in nearly all beyond the limits of the tropics, cold is 
regarded rather as an enemy to be repelled, than as an ally to be courted. 
Its most familiar applications are to check or prevent the putrefaction 
of organic substances, or to subserve the uses of luxury. For neither of 
these purposes is it usually necessary to secure a temperature very 
greatly depressed below that of the ambient air. Nor, if it were so, 
would the means of accomplishing the object be generally within the 
reach of those who would desire to profit by them. To command a 
superior temperature is easy. Combustion furnishes heat in quantity 
practically exhaustless, and though skill may be of use in securing its 
economical production or application, none whatever is necessary in 
order to set the process in ox)eration. But the means of creating artifi- 
cially a temperature extremely depressed are neither simple nor familiar, 
and to employ them successfully at all requires a species of knowledge 
and a degree of scientific skill which are rarely found except with the 
experimental chemist. There are certain industries, however, of which 
the process of refrigeration forms a part, Avhich do not require a temper- 
ature inferior to that which prevails in the atmosphere, or in the run- 
ning waters of the earth at the same time. 



362 PARIS UNIVERSAL EXPOSITION. 

The ideas conveyed by the words cold and hot are related to our senses 
merely, and not to anything absolute in the condition of bodies. It is 
a familiar experiment to place upon the table three vessels of water, one 
of them at the temperature of freezing, another as hot as the hand can 
bear, and a third at the temperature of the weather. The experimenter 
at first immerses one hand in the hot fluid and the other in the cold; 
after the lapse of a minute or two he places both together in the water of 
mean temperature, and he is conscious at once of the paradox of perceiv- 
ing the same liquid to tje apparently both hot and cold at the same time. 
In the working of a steam-engine the condenser supplied with water from 
natural sources is cold relatively to the steam to be condensed. For all 
ordinary distillations the natural temperature furnishes sufficient refrig- 
eration. 

For certain purposes the natural temperature of the colder season 
suffices, but not that of the warmer. For such, to a limited extent, it is 
practicable, by careful contrivances, to preserve the winter temperature 
throughout the year. This is done by collecting ice in the season of its 
abundance, and storing it away in magazines with non-conducting walls, 
sunk usually beneath the surface of the earth. It is by means of ice 
thus preserved that the low temperature required in refrigerators for 
domestic uses is maintained; and such ice furnishes also the essential 
element in the most simple and best known of freezing mixtures — that 
which is employed by confectioners — a mixture of ice-powder and com- 
mon salt. This mixture produces a depression of temperature nearly 
18° C below that of freezing water. It is the temperature which was 
adopted by Fahrenheit as the zero of his thermometer. 

The cause of the cold produced by freezing mixtures is to be sought 
in the absorption of heat which accompanies the transformation of bodies 
of every kind from the solid to the liquid state. This heat becomes 
latent; that is to say, it does not raise the temperature of the substance 
into which it passes. On the contrary, when the substances mingled 
are such (as for the purposes of a freezing mixture they must be) as 
when in union to remain liquid at a temperature much below that at 
which they solidify when pure, they will, in liquefying, draw upon their 
own sensible heat and upon that of bodies in contact with them for the 
latent heat necessary to their liquefaction ; and it is thus that they pro- 
duce the refrigerating effect from which they derive their name. Saltpetre 
and common salt, or saltpetre and sal ammoniac, added to three times 
their weight of water, will depress the temperature of the solution 
22° 0. If to this solution be added once and a half as much sulphate 
of soda as of either of the salts previously used, the temperature will 
sink three or four degrees lower. Equal parts of carbonate of soda. 
nitrate of ammonia, and water will produce a depression of 32° 0. And 
three parts of phosphate of soda with two of nitrate of ammonia and a 
little more than one of water, will sink the thermometer nearly 40° C. 
This depression of temperature is to be understood onlv of the solution 



ARTIFICIAL PRODUCTION OF COLD. 363 

itself, on supposition that it draws no heat from the substances in con- 
tact with it. The latent heat of liquefaction for a given weight of mate- 
rial liquefied is but a determinate amount. When, therefore, a solution 
is employed as a means of refrigerating other things, the degree of cold 
will be less considerable in proportion as the quantity of matter to be 
chilled is greater. And in general it will be found that the useful effect 
produced will not be sufficient compensation for the trouble and expense 
of the operation, if it is proposed to apply the process on a very large 
scale. 

As heat becomes latent whenever a body passes from a solid to a liquid 
state, so a much larger amount is similarly absorbed when a liquid 
becomes a vapor. There are a large number of liquids, moreover, which 
evaporate so freely as to produce a very sensible degree of cold without 
any special arrangements to favor this result. If one hand be moistened 
with water while the other remains dry, the moistened hand will be very 
perceptibly colder than the other. If the fluid used to moisten the hand 
be alcohol instead of water, the sensation will be much more marked ; 
and if, instead of alcohol ether be substituted, it will soon become intol- 
erable. A current of air blowing upon the moistened surface will accel- 
erate the evaporation and increase the intensity of the cold. And a 
removal or diminution of the atmospheric pressure upon the surface of 
the liquid will have a similar effect. Pressure and variation of pressure 
exercise indeed a most marked influence upon the formation of vapor. 
The particles of most liquids are constantly tending to assume the gase- 
ous form. To a certain extent this tendency is efficient at every tem- 
perature to which observation has been carried; but there are two causes 
by which it is usually held more or less in check, viz : the force of cohe- 
sion and the pressure superincumbent on the surface. This tendency 
diminishes, it is true, as the temperature is more depressed; but with 
none of the more volatile liquids, nor even in the case of water, has there 
been experimentally found a point at which it wholly ceases to exist, or 
at which the fluid becomes absolutely fixed. Evaporation goes on from 
the surface of snow at the temperature of 0° G, in the open air and in a 
perfectly still night, at the rate of nearly thirty grams, or about an Eng- 
lish ounce, per square metre of surface exposed per hour. At the zero 
of Fahrenheit, 32° F below freezing, evaporation goes on at the rate of 
something like seven and a half grams per square metre per hour; 
and even at — 32° F it continues still to be sensible, amounting to 
not less than a quarter of a gram per square metre per hour. Trivial 
and insignificant as this slight evaporation may seem, it neverthe- 
less, when extensive surfaces are considered, produces large effects. 
At the extremely low temperature last named, there rises hourly, 
from every acre of surface exposed, more than a kilogram of water 
in the form of invisible vapor ; and from every square mile between 
six hundred and seven hundred kilograms, or from thirteen hundred to 
fifteen hundred pounds. The elastic force of the vapor thus formed 



364 PARIS UNIVERSAL EXPOSITION- 

inereases with the temperature. When this force is equal to the pres- 
sure of the atmosphere evaporation is attended with ebullition, an effect 
produced by the escape of bubbles of vapor formed beneath the surface 
of the liquid. In this state of things there is nothing to prevent the 
whole mass of the liquid from bursting into vapor in the same instant, 
except the necessity of drawing from the surrounding matter the large 
amount of heat which is necessary to constitute its latent heat of elas- 
ticity. This requires time, so that ebullition is a continuous process. 
Under the ordinary pressure of the atmosphere at the earth's surface, 
water boils at 100° G, or 212° F. In passing into vapor at this temper- 
ature it absorbs, without any elevation of its own sensible temperature, 
an amount of heat sufficient to raise the same weight of water without 
vaporizing it 537° C, and this is the measure of the latent heat of steam. 
If we could suppose a quantity of water enclosed in a cavity which it 
should entirely fill, but could not burst, to be heated up to 637° 0, and 
then allowed vent, this liquid in its escape from its confinement would 
issue, not in a vapor formed by ebullition, but with an instantaneous 
explosion like that of gunpowder. The temperature would at the same 
time fall at once to 100° C. 

Under a pressure less than that of the atmosphere, ebullition takes 
place at a lower temperature. Were two-thirds of the atmospheric 
pressure removed, water would boil at ordinary summer heat. A vessel 
of water placed under the receiver of an air-pump, which is then exhausted 
of air, speedily enters into ebullition ; but, unless the machine is kept 
constantly in action, the vapor which is thus formed will restore very 
promptly the pressure upon the surface which has been removed by the 
exhaustion. If, however, the pump is powerful enough to carry off the 
vapor as fast as it is formed, and is steadily worked, the heat Avhich the 
rising vapor withdraws from the water will presently reduce the tem- 
perature to the freezing point, and the liquid will be converted into ice. 

The mode of preparing ice in Bengal, which is mentioned in every 
elementary book on physics, has been explained by attributing the 
depression of temperature to evaporation. This mode consists, as is 
well known, in exposing water in shallow vessels by night beneath the 
clear skies of India to the open air. A large plain unobstructed as much 
as possible by trees or buildings, is selected for the purpose, in which 
pits or excavations twenty or thirty feet square and two feet deep are 
sunk, the floors being covered with dry stalks of corn or sugar cane. 
Upon these are placed the water vessels, constructed of porous earthen 
ware, and not much more than an inch deep. In the morning, if the 
sky has been clear, the vessels are found to contain thin plates of ice. 
which are carefully gathered and stored away. This process was suc- 
cessfully imitated in England in the latter part of the last century by 
Dr. Wells, author of the Essay on Dew ; and soon afterward an attempt 
was made in France to employ it for the systematic manufacture of ice. 
but the undertaking proved to be economicallv a failure. 



ARTIFICIAL PRODUCTION OF COLD. 365 

The cold produced in the circumstances here described is in a measure 
owing* to the evaporation of the water, and it is for the purpose of pro- 
moting this evaporation that the vessels employed are formed ot an 
earthen ware which is exceedingly porous. Similar vessels have been 
used almost from time immemorial in Egypt, in India, and in southern 
Europe, to hold the water used for summer drinking, which they main- 
tain at a temperature refreshingly cool, in consequence of the continual 
evaporation from their surfaces of the water which exudes through their 
pores. But evaporation is not the most important agency in the pro- 
duction of the ice collected in this way by the Hindoos. Evaporation 
may go on no less rapidly when the sky is obscured by clouds, and yet 
in that case there will be no formation of ice. The same negative result 
will follow in the clearest nights, unless the air be tranquil as well as 
clear, though wind accelerates evaporation to a marked degree. It is 
the loss of heat by radiation into open space, which, in the absence of 
the sun, is constantly going on without compensation, which, more than 
any other cause, determines the congelation. This suggests the import- 
ance to the success of the process of the excavations in Avhich the vessels 
are placed. In these the air at the earth's surface, which is always under 
such circumstances colder and therefore denser than that above, is 
retained at rest as a liquid is held by its containing vessel, and prevented 
from mingling with the warmer air, as it would otherwise do under the 
influence of light atmospheric currents. Strong winds, however, prevent 
the air from stagnating even in deep valleys ; and hence, on windy 
nights, the process of natural freezing in summer fails ; yet on windy 
nights evaporation is greater, and on still nights it is less, than the mean 
in the Indian ice pans, other things being equal; the check which, in the 
last case, the process receives, being consequent upon the saturation of 
the air stratum which rests upon the water. 

Radiation, liquefaction, and evaporation are then the three causes by 
which the temperature of bodies may be depressed. To these may be 
added the rapid dilatation of elastic fluids on a sudden reduction of 
pressure. A striking illustration of this last effect is furnished in a 
hydraulic machine at Chemnitz in Saxony, described in most elementary 
books on physics, in which air is highly compressed in a closed reservoir 
by means of a column of water. If a stop-cock in this reservoir be sud- 
denly opened, the expanding air rushing out produces a degree of cold 
sufficient to freeze the drops of water which it brings along with it into 
pellets of ice. 

To take advantage, however, of any of these means of producing cold 
for any useful purpose, and upon a large scale, is not a problem by any 
means easy of solution. To congeal water by its own evaporation under 
the air pump, with no means of removing the vapor as it forms except 
the action of the pump itself, is not practicable unless with such pro- 
portions between the barrel of the pump and the receiver as are not 
conveniently realized. The result is reached with more facility if some 



366 -PARIS UNIVERSAL EXPOSITION. 

expedient be resorted to for absorbing- the vapor as rapidly as it 
is produced ; and this is practicable by introducing into the receiver 
such substances as have a great affinity for water, as, for instance, anhy- 
drous chloride of calcium, or concentrated sulphuric acid. It was by 
the use of sulphuric acid that the congelation of water by its own evapo- 
ration upon the air pump was first experimentally shown to be a pos- 
sibility. The experiment is due to the late Professor Leslie of Edin- 
burgh, having been made by him in 1810. It is easily repeated by placing 
a vessel of thin material, partially filled with water, upon a light sup- 
port beneath the air-pump receiver, while within the same receiver is 
arranged a considerably larger vessel containing the concentrated acid. 
Both the liquids should present a comparatively broad surface. On work- 
ing the machine the exhaustion proceeds with sensibly the same rapidity 
as in a vacuum, the vapor being taken up by the acid instantaneously. 
The water enters almost immediately into ebullition, and in a very short 
time becomes solidified into a mass of porous ice. This interesting 
experiment has remained almost down to the present time among the 
curiosities of the scientific lecture-room, without leading to any practi- 
cally useful application. In the present Exposition, however, we have 
seen it employed, with only a modification of the form of the apparatus 
and of the dimensions of the essential parts, in such a manner as to pro- 
duce ice in considerable quantities and at a very cheap rate. The appa- 
ratus is exhibited in action by Mr. Edmond Carre, of Paris, whose brother, 
Mr. Ferdinand Carre, exhibits also much more powerful contrivances 
for the same purpose, deriving their efficiency from a different principle, 
which will be presently described. 

II.— ARTIFICIAL PRODUCTION OF ICE. 

CARRE'S SULPHURIC ACID APPARATUS. 

Mr. E. Carre's sulphuric acid apparatus is shown in its essential parts in 
the accompanying figure. Its use is to j>roduce the carafes f rappees, 
frozen decanters, so frequently seen in Paris. It consists of a large 
vessel, resembling the boiler of a steam-engine, which is designed to 
contain the concentrated sulphuric acid ; of an air pump with tube con- 
nections to be adapted to the wide mouths of the carafes, and of a mech- 
anism by which the lever of the air-pump is made to keep the acid in 
continual agitation. The great volume of the acid renders the loss of 
absorptive power by dilution very slow, and the constant agitation pre- 
vents the formation of a superficial dilute stratum, which, in the ordinary 
experiment, interferes materially with success. The apparatus is easy 
of management and does its work very rapidly. With that exhibited, 
twelve or more flasks containing a pint of water each were frozen in 
presence of the public in three minutes. The acid continues to act well 
till it becomes diluted to the fiftieth degree of Baume's hydrometer, 
which corresponds to a solution containing two parts of water to three 



SULPHURIC ACID FREEZING APPARATUS. 



367 



of the strongest hydrated acid. If, therefore, the reservoir contains 
originally one hundred and fifty pounds of the concentrated acid, it will 
only require to be charged anew after having absorbed one hundred 
pounds of water in the form of vapor. The evaporation of such a mass 
of water would cause an absorption into the latent form of as much heat 
as is given out by the conversion of five hundred and seventy pounds of 
water, taken at 60° F, into ice. An apparatus constructed on this scale 
should therefore theoretically furnish this same amount of ice at the 
temperature of freezing before any change of the charge of acid becomes 
necessary. Practically, however, the production will be considerably 
less, since a sensible amount of heat will be drawn from the substance 
of the vessels containing the water, and furnished by radiation from 
surrounding objects. Allowing seventy pounds for the loss from this 
cause, we might put the productive power of the apparatus, before 
renewing the acid, at a quarter of a ton. The acid holder required for 
an apparatus of this magnitude will be about thirty inches in length 
and fifteen inches in diameter internally. It is constructed of a material 
which resists the action of the acid, being chiefly lead, but containing 
a slight alloy (five or six per cent.) of antimony. 

In the annexed figure A de- 
notes the reservoir of acid; F, 
a carafe or flask of water con- 
nected with the apparatus by 
the tube r r' r" having a stop- 
cock at L. F is the barrel of 
the air-pump, and H its lever, 
which, by means of the connec- 
tions m ft, causes the agitator 
efghto oscillate. The rod p 
jp', which forms the axis of mo-g 
tion, passes into the cylinder 

D' through a Stuffing box. At Carr6 ' S Sul P hudc Acid Freezin * Apparatus. 

I) is seen another shorter vertical cylinder which is closed at top by 
a glass plate fitted on air-tight. This is to afford an opportunity of 
examining the interior of the apparatus while it is in action. 

Though this contrivance was employed in the Exposition for no other 
purpose but to freeze water in bottles, it is evident that by adopting 
such a form of vessel as should permit the ice to be extracted from it, 
as for instance a vessel cylindrical or conoidal in shape, with caps ground 
on, it might be made more generally useful. The inventor estimates the 
cost of production at six centimes per kilogram, which is about half a 
cent a pound. This estimate supposes, however, that the sulphuric acid 
undergoes only a moderate depreciation of value in consequence of its 
dilution. For many purposes its usefulness is not at all impaired ; though 
to restore it to its originally concentrated condition would be attended 
with considerable expense. 




368 PARIS UNIVERSAL EXPOSITION. 

The apparatus in the Exposition was worked by hand. If constructed 
on a large scale and kept in continuous operation, it would require some 
form of motor to drive it. 

The inventor constructs several sizes of the apparatus, at prices increas- 
ing with their power. 

Francs. 

No. 1. Apparatus without lever pump and with 1 flask 120 

No. 2. Apparatus without lever pump and with 2 flasks 150 

No. 1. Apparatus with lever pump and with 8 flasks 700 

No. 2. Apparatus with lever pump and with 12 flasks 900 

Mr. Carre will furnish also still larger models to order, up to a capa- 
city of one hundred kilograms per hour. 

The sulphuric apparatus of Mr. Edmond Carre will not, however, com- 
pare in importance with the larger and greatly more complicated contri- 
vances of his brother, Mr. Ferdinand Carre, for the same purpose, which 
were exhibited in a building erected expressly for them in the park of 
the Exposition. This machinery throughout the continuance of the 
Exposition was constantly producing huge blocks of ice, not merely 
congealed but depressed in temperature at the same time many degrees 
below the freezing point. The efficient cause producing cold in this 
apparatus, as in the other, is evaporation ; but the liquid employed is 
ammonia, a substance which is not only vastly more volatile than water, 
but under ordinary atmospheric pressure, is, in fact, permanently gase- 
ous. Gaseous ammonia is reduced to the liquid form by pressure ; but 
at 20° C (68° F) it requires a pressure of not less than eight and a half 
atmospheres to produce liquefaction, and at 25° C (77° F) not less than 
ten. Thus the pressure required rises very rapidly with the tempera- 
ture. On the other hand, to liquefy ammonia by cold merely, under the 
ordinary atmospheric pressure, requires a reduction of temperature down 
to 38°.o below zero of the Centigrade thermometer. Ammonia, therefore, 
evaporates very rapidly even at temperatures extremely low ; and as the 
latent heat of its vapor is great, being estimated at 511° C. it may be 
used as a powerful means of producing cold, provided any practicable 
method can be devised for removing the vapor as it is formed. To do this 
mechanically would require a pump of large dimensions ; aud inasmuch 
as considerations of economy as well as of health and the comfort of the 
operators would require that the vapor should be reduced by compres- 
sion to the liquid state, the pump should be capable of exerting a pres- 
sure of from seven to ten atmospheres. If, therefore, it were only by 
mechanical means that ammonia could be condensed, this substance 
could not be profitably used as a means of producing cold. But the pro. 
perty which water and some other substances possess of absorbing animo- 
niacal gas in great volume and with singular rapidity, furnishes a means 
of condensing it without the necessity of employing any mechanical 
power. By taking advantage of this property intense cold may be pro- 
duced with very simple arrangements. The fact was first illustrated bv 



carre's ammoniacal freezing apparatus. 369 

Faraday in 1823, and it has been a familiar lecture-room experiment 
ever since. Chloride of silver, at low temperatures, absorbs many times 
its volume of dry ammoniacal gas. At 60° F, (15|° C) the absorp- 
tion amounts to more than forty volumes. But at the temperature 
of 100° F (37|- 0) this gas is entirely expelled from the compound. 
If now a quantity of the chloride which has become saturated with ammo- 
nia at 60° F, or lower, is placed in the closed end of a strong glass tube 
bent at an angle, or in the form of an inverted siphon, and if the other 
branch be freed of air by slightly warming the compound, and the tube 
be afterwards hermetically sealed, then by heating the mass of chloride 
up to 100° F, or above, the whole of the ammonia may be driven from 
it, while, supposing the other arm of the tube to be at the same time 
immersed in a refrigerating bath, the pressure produced will cause the 
gas to take the liquid form. This experiment, which is not an unsafe 
one, provided the tube be of moderate dimensions, allows the progress 
of the condensation to be observed. The liquid formed is seen to be 
colorless, very fluid, and with a refracting power superior to that of 
water. Its specific gravity is stated by Faraday at 0.76. If, now, after 
the gas has been all driven over, the extremity of the tube containing 
the chloride be immersed in the refrigerator, and that containing the 
liquid placed in a vessel of water, the liquid ammonia will immediately 
commence boiling and will continue to boil until the whole has dis- 
appeared, the chloride re- absorbing the vapor as fast as it is formed ; and 
in consequence of the intense cold created by this rapid evaporation, the 
water surrounding the tube will be converted into ice. 

But this material could not be economically employed in producing 
artificial cold. A given quantity of chloride of silver would produce 
only about the thirtieth part of its bulk of liquid ammonia, and a fifth 
part of its bulk of ice at 0° O. In order to produce a kilogram of 
ice, it would be necessary to employ twenty-seven and a half kilograms 
of the chloride ; and this supposes the operation to be conducted 
with no loss. Water, on the other hand, dissolves, at moderate temper- 
atures, seven hundred times its volume of the gas, a quantity capable 
of producing two-thirds of its bulk and half its weight of liquid ammo- 
nia, and of converting into ice more than three times its own bulk. A 
kilogram of water employed as a solvent of ammoniacal gas will thus 
suffice to produce three kilograms of ice. 

In speaking of quantities of heat as transferred from one body to 
another, or in comparing the quantities of heat absorbed by different 
bodies, or yielded up by them in undergoing changes of temperature, it 
is convenient to fix upon some determinate quantity as a unit of reference. 
By common consent, the amount of heat required to raise the tempera- 
ture of a kilogram of water, taken at 0° O of temperature, one degree 
Centigrade, an amount which is also very nearly constant whatever be 
the initial temperature, has been adopted to serve as such a unit. To 
this unit the French have given the name calory, and the convenience 
24 i a 



370 PARIS UNIVERSAL EXPOSITION. 

of the term is securing for it general adoption and use with the physicists 
of other countries. Instead of the kilogram and the degree Centi- 
grade, English writers have been in the habit of employing the pound 
avoirdupois and the degree of Fahrenheit's thermometer; but the two 
units are easily convertible into each other, and this latter mode of com- 
puting is at present going out of use. 

It may thus be stated that the latent heat of a kilogram of liquid 
ammonia is equal to ninety calories. The latent heat of a kilogram of 
its vapor, that is to say, of ammoniacal gas, amounts to five hundred 
and fourteen calories. The latent heat of water, liberated in the act 
of congelation, is equal to seventy-nine calories per kilogram ; so that 
one kilogram of ammonia would be capable by its evaporation of freez- 
ing six and one-half kilograms of water taken at the initial tempera- 
ture of zero ; or five kilograms taken at the temperature of 21° C, 
(75°.2 F.) 

CARRE'S AMMONIACAL FREEZING APPARATUS. 

Mr. Carre constructs two forms of apparatus for freezing in which 
ammonia is the efficient instrumentality. One of these is intermittent 
in its action, and the other continuous — that is to say, this latter form 
furnishes an uninterrupted supply of ice at a determinate rate per hour: 
or if applied to produce cold for any other purpose, it absorbs per hour 
a given number of calories, while the duration of its operation is capa- 
ble of being extended at pleasure. 

The intermittent apparatus is represented in the annexed figure. In 
its principle and in its mode of use, it is but a reproduction of the experi- 
ment of Faraday with the bent tube described above. The difference is 
only in the form of the apparatus, and in the substitution of aqua 
ammonia in place of chloride of silver saturated with ammoniacal gas. 
In the figure herewith presented, the two extremities of Faraday's tube 
are shown to be replaced by a boiler and a refrigerator. This model is 
designed only for operations on a small scale 5 the largest producing at 
each operation but two kilograms of ice, and the smallest only half a 
kilogram. It is therefore moderate in dimensions, and portable in 
form. An apparatus to produce two kilograms of ice would require 
the evaporation of two-fifths of a kilogram or four hundred grams of 
liquid ammonia. As this requires twenty times its own weight of water 
to form a solution of the necessary strength, the capacity of the boiler 
must be such that it will conveniently receive eight and a half kilo- 
grams of the solution — that is to say, it must hold at least eight and 
a half litres, or two gallons and a quarter, of liquid. But. as the rapidity 
of the operation is promoted, especially when the freezing is going on. 
by exposing a large surface of water to the ammoniacal vapor. Mr. 
Carre, in the earliest forms of this apparatus, made the boiler of at least 
twice the dimensions required to contain the quantity of fluid employed. 



AMMONIACAL FREEZING APPARATUS. 



371 



and fixed within it a series of flat shallow basins, with openings in the 
middle, by which each could overflow into the one below. When the 
solution was introduced at the top, these vessels were successively filled 
by such overflow; and thus the solution was divided into a number of 
strata, with a free space between. A different expedient, to be mentioned 
presently, has more recently been adopted, rendering it unnecessary 
to employ a boiler greatly exceeding in capacity the volume of the solu- 
tion. If we allow twelve litres of capacity to a boiler designed to receive 
eight and a half litres of solution, there will be abundance of free space; 
and the quantity of solution may be sufficiently increased above the 
exactions of theory, to compensate for all losses. Such a boiler would 
have eighteen centimetres of diameter and forty of height — say seven 
and a quarter inches by sixteen. 

The refrigerator requires to be constructed so as to present a large 
surface toward the vessel containing the water to be frozen. It is formed 
of an outer shell in shape slightly conical, with a cylindrical receiver 
within. The annular wedge-shaped space between the cone and the 
cylinder forms the condenser which is to contain the liquefied ammonia. 
The cylindrical cavity in the interior is intended to receive the vessel 
containing the water. This vessel should fill the entire cylinder so far 
as' convenience will allow, and the remaining space should be filled by 
some liquid not liable to congeal Fig. 85. 

and having a low specific heat. 
Alcohol fulfils this condition, 
though there are saline solutions 
which are cheaper but absorb more 
heat. In some of his refrigerators, 
Mr. Carre introduces what the fig- -, 
ure does not show, a succession of 
little conical shaped receivers with- 
in the condenser, which form a row 
of collars round the cylindrical 

inner wall, so arranged as to fill Carrfe , 8 Ammoniaca i FYeez[ng Apparatus for 
successively with the condensed families 

liquid, and thus to present a larger evaporating surface when the refrig- 
erating process begins. 

The boiler and the refrigerator are connected by a tube which receives 
the liberated gas at the top of a cylindrical dome surmounting the boiler. 
This appendage is designed to allow opportunity for the steam which 
rises along with the gas to become condensed, and to return again to the 
boiler in the form of water, which in great measure it does. The con- 
necting tube enters the refrigerator near the top also. To give steadi- 
ness and strength to the apparatus an intermediate brace is introduced 
between the boiler and the lower part of the connecting tube; and this 
serves conveniently as a handle. 

After what has been said, the mode of employing the apparatus hardly 




372 PARIS UNIVERSAL EXPOSITION. 

requires description. There are necessary a suitable portable furnace, 
and a large tank to serve as a condensing refrigerator. This tank is to 
be filled from any natural source with water at the ordinary tempera- 
ture. The boiler charged with the solution is placed over the furnace, 
and the apparatus is first "purged" — that is to say, cleared of air. 
This is done after the temperature of the boiler has been somewhat 
raised, by turning a stop-cock (not shown in the figure) which allows 
the air to pass off as the gas set free by the heat fills successively 
the different parts of the apparatus. The expelled air is conducted 
by a tube into a vessel called the " purger," where it is discharged 
beneath the surface of water. Any ammonia which may pass over 
with it is dissolved by the water and saved. When the purging is 
complete, the stop-cock is closed, and the temperature is steadily raised 
until the thermometer connected with the boiler indicates 130° or 140° 
C, at which latter temperature hardly a trace of ammonia will remain in 
the solution. The refrigerator, which during this time has continued to 
be immersed in the tank, will now contain the ammonia in a liquid form ; 
and as the temperature of the water bath will probably be not far from 
20° C, the tension of the vapor will be about eight or eight and a half 
atmospheres. The apparatus at this stage of the operation is to be re- 
moved from the furnace, and the boiler to be placed in its turn in the 
water bath. The temperature of the boiler will rapidly fall, and as it 
does so, the power of the water to absorb ammoniacal vapor will be re- 
stored. The gaseous ammonia will be rapidly redissolved, reducing the 
pressure upon the liquid, which will evaporate with corresponding ra- 
pidity, drawing for its latent heat upon the sensible heat of the water 
to be frozen. The result will be, the complete evaporation of the lique- 
fied ammonia, and the restoration of an aqueous solution in the boiler, 
of the original strength. The vessel containing the water to be frozen, 
and the alcohol which is to surround it, should be introduced only after 
the first part of the operation has been completed. They may otherwise 
have their temperature raised by the development of heat which occurs 
during the condensation of the ammonia, and this would involve, so far 
as it goes, a needless loss. During the congelation the refrigerator must 
be surrounded by a non-conducting envelope, in order to protect it 
against radiation, and to secure it from receiving heat from the air. 

What capacity should be given to the tank will depend upon whether 
or not the operation is conducted with the advantage of an unfailing 
water supply from a natural source. If that is the case a tank of mode- 
rate dimensions will answer the purpose ; provision being made for con- 
stantly renewing the supply of cold water, as that which has become 
heated in the process is withdrawn. But if the tank is to be charged 
once for all, and to be used from beginning to end without change of the 
water, then its size must be considerably increased. We may easily cal- 
culate, in the present instance, what quantity of water it ought to con- 
tain. The water of the bath may be assumed to have originally a n-m- 



AMMONIAC AL "FREEZING APPARATUS. 373 

perature of 17° (62°. 6 F.) It must be sufficient in quantity to absorb 
all the heat withdrawn from the ammonia during liquefication and from 
the boiler during the congelation, without having its own temperature 
raised above, say, 25° C. 

The ammoniacal gas condensed comes over at a temperature varying 
from 20° C to 140° 0, say, at a mean, 80° 0. The temperature after con- 
densation should not exceed 20° C. Hence it must lose 60° of sensible 
heat, and as the capacity of the gas for heat, compared with water, is 
only 0.508, it transfers by such depression thirty calories per kilogram 
to the water of the tank, or for two-fifths of a kilogram, twelve calories. 
The latent heat for the same quantity of liquid will amount to two hundred 
calories, (in round numbers,) and the whole will be two hundred and 
twelve calories. Supposing the same bath used to chill the boiler, we 
shall have to cool down eight kilograms of water from 140° O to 25° C, 
say 115°, and also to absorb once more the two hundred calories of latent 
heat evolved by the gas in dissolving in the water. To this must be 
added the heat given up by the metal of the boiler itself. If we suppose 
this metal to weigh five kilograms, which is a large allowance, it will 
be equivalent to increasing the weight of water to be cooled by half a 
kilogram, since the specific heat of iron is only about one-tenth of that of 
water. We shall have then 115° x 8.5= 977.5 calories for the cooling, 
and to this we must add two hundred calories for the re-solution of the 
gas, making in all 1,177.5 calories. 

The gas dissolved will come over at a temperature varying from 20° C 
to — 10° C, which will be at a mean 20° below the ultimate temperature 
of the bath; but the gain from this cause will be slight, amounting only 
to four calories and may be neglected. Uniting the results, we shall 
see that the total amount of heat to be abstracted by the bath is 1,389.5, 
say 1,390 calories. As we take the water originally at 17° C, and suppose 
it not to have gained in the end a higher temperature than 25° O, (which 
is an advance of 8°,) the number of litres of water that we need will be 
found by dividing 1,390 by 8, which will give 173.75, or, reduced to gal- 
lons, about thirty-eight gallons. Of course, without much loss, we may 
allow a larger change of temperature to the bath. A bath of twenty gal- 
lons would do nearly as well, and would have an ultimate temperature of 
less than 33° O, (about 91° F.) An allowance must also be made for 
inevitable losses by radiation and conduction, so that an apparatus 
designed to produce two kilograms of ice at an operation should have 
a theoretic capacity equal to something like two and a half. 

The prices at which Mr. Carre furnishes the different styles of this 
apparatus are not exactly proportional to their capacity. The larger 
styles are proportionally cheapest. For an apparatus of the capacity of 
a kilogram at an operation, complete in all its parts, including furnace, 
tank, ice-holder or freezer, envelope and two thermometers, and delivered 
in Paris packed for transportation, the price is 282 francs, or about $56 
For one of double this capacity, similarly complete, it amounts only to 
106 francs, or about $81. 



374 PARIS UNIVERSAL EXPOSITION. 

The cost of ice produced in this way Mr. Carre puts at from three to 
five centimes, according to the price of coal. We may make the calcu- 
lation for the case of the apparatus of two kilograms which we have 
been considering. We have to heat eight kilograms of water and five 
kilograms of iron from 17° to 140° 0, say through a range of 123°. 
This demands one thousand and forty-five calories. We have also to 
supply two hundred calories in latent form to the gas set free, and to 
raise this also in sensible heat from the original temperature of 17° 
to a mean temperature of 80° C, which will require thirteen calories 
more. The total amount of heat which the apparatus will necessarily 
draw from the furnace will be, therefore, only one thousand two hun- 
dred and fifty-eight calories. As a kilogram of coal furnishes eight 
thousand calories, 1 about a sixth part of a kilogram, or one-third of a 
pound avoirdupois, would furnish all the heat needed. A ton of coal 
costs us six or eight dollars — more usually the latter sum. One third of 
a pound of coal, at eight dollars per two thousand pounds, would cost 
a cent and a third. This exceeds Mr. Carre's estimate, and it leaves out 
of account the prime cost of the apparatus and that of the ammonia. 
Moreover, it is to be considered that a fire cannot be made in a furnace 
eight or ten inches in diameter, and maintained for an hour and a half 
(the duration of the operation) with the consumption of only this small 
amount of coal ; and that of the heat which the furnace generates a very 
large proportion — certainly more than half, and probably fonr-fifths — 
passes off through the flue, or escapes by radiation ; so that, in point of 
fact, the ice produced in this apparatus will cost several cents per kilo- 
gram, instead of three to five centimes. The only mode of diminishing 
this cost would be to have a double apparatus for a single furnace, and 
to perform several operations successively without extinguishing the 
fire. 

It was observed in the early part of the foregoing description that 
Mr. Carre's original boilers were provided with a number of shallow 
basins in the interior, arranged one above the other, in order to present 
a large absorbing surface of liquid during the process of congelation. 
He has more recently provided, by a very simple but effectual expedi- 
ent, to secure an instantaneous absorption of the gas without the aid of 
this system of basins. The diificulty when the whole body of the liquid 
was in a single mass in the boiler was, that a very strong solution 
formed upon the surface, and, being lighter than the water beneath, cut 
off communication between the gas and the unsaturated water. In the 
new form of the apparatus the inventor has introduced a diaphragm 
into the neck of the boiler, by means of which he is able to prevent the 

1 The heating power of different coals is very unequal. That of the long-flame eaunel 
coal, of Coventry, was put by Tredgold at nine thousand five hundred calories : common 
coal of good quality may be taken at seven thousand : charcoal gives six thousand. This 
last number is commonly taken to represent the heating power of mineral coal, in order that 
the error of calculation, if any, may be on the safe side. 



CONTINUOUS FREEZING APPARATUS. 375 

gas from descending, in any way except through a tube which, passing 
through the diaphragm, is continued nearly to the bottom of the boiler. 
The gas is thus conducted to that part of the liquid which is in condi- 
tion to seize it with the greatest avidity, and its absorption is corre- 
spondingly rapid. 

There can be no doubt that contrivances of this kind must be very 
useful and even economical in countries where ice cannot be collected 
during the summer. Their usefulness ought not to be measured by the 
contribution which they make to human luxury, or even to human com- 
fort. They cannot fail, for instance, to be often of great advantage in 
the laboratories of chemists and in hospitals for the sick ; and they must 
be especially valuable to surgeons accompanying armies in the field. 

It is a disadvantage that the operation of the apparatus is not expe- 
ditious. For an apparatus of the capacity of a kilogram the furnace 
operation requires an hour, and the process of congelation another hour. 
If two kilograms are prepared at once, the time consumed from begin- 
ning to end will not be less than three hours. 

It is to be observed that along with the gas, during the furnace ope- 
ration, there passes over, inevitably, some watery vapor, which con- 
denses first into water, and then forms ice in the refrigerator. The 
amount of ice thus formed is to be counted among the losses j but after 
the operation is over, it must be reliquified and returned to the boiler. 
This may be effected by placing the apparatus for a time in a position 
which will allow the water to flow back through the connecting tube. 

CARRE'S CONTINUOUS FREEZING APPARATUS. 

The two kinds of apparatus above described for producing artificial 
cold are interesting and have their value ; but they cannot be said to pos- 
sess a great industrial importance. The same is not true, however, of the 
continuously acting apparatus of Mr. Ferdinand Carre, which is on a 
much larger scale than either, and is, in fact, one of the most valuable 
contributions which science has yet made to the promotion of human 
comfort, and to the progress, in certain forms at least, of industrial art. 
Indeed, when the apparatus is examined in its details, and the ingeni- 
ous felicity with which the difficulties involved in the problem have 
been met is understood and appreciated, this invention cannot fail to be 
recognized as presenting one of the most admirable illustrations of the 
combination of scientific knowledge with practical skill which the Expo- 
sition presented. 

This, therefore, is the proper place to claim for America the credit of 
having originated an invention so beautiful and so useful ; and which, 
however much it may have owed to the enterprise and skill and to a 
certain extent to the genius of Mr. Carre in achieving for it a commercial 
success, was nevertheless patented many years ago, both in England and 
in the United States, and was subsequently constructed, in a form 
embracing all the essential features of the apparatus of Mr. Carre, by our 



376 PAEIS UNIVERSAL EXPOSITION. 

countryman, Professor Alexander 0. Twining of .New Haven. In the 
apparatus actually constructed by Professor Twining the volatile liquid 
employed in refrigeration was sulphuric ether; hut his patent covered all 
volatile liquids, including ammonia and carbonic acid ; and the differ- 
ences between it and that which we are about to describe are only such 
as the differing properties of the two substances naturally suggest. For 
purposes of comparison, Professor Twining's apparatus will be more fully 
described further on. The material for the description has only come 
into the possession of the writer since his return to this country, while 
this account of the invention of Mr. Carre was prepared in Paris in the 
summer of 1867. 

Mr. Carre's continuous process, like the intermittent, depends then for 
its efficacy upon the evaporation of liquid ammonia. In both processes 
the liquefaction is effected in substantially the same way. Aqua am- 
monia is introduced into a boiler, and the gas is expelled by heat into a 
condenser ; but in order that the process may not be arrested by the ex- 
haustion of the solution, the impoverished liquid is gradually withdrawn 
from the bottom of the boiler, while a corresponding volume of a fresh 
and strong solution is constantly flowing in at the top. The condensa- 
tion is produced by the united effect of cold and pressure. From the 
condenser, the ammonia in a liquid state passes on to a refrigerator, in 
which are placed vessels containing the water to be frozen ; and as the 
boiler and the condenser keep up an unfailing supply of the liquid, so 
the refrigerator will continue to freeze successive masses, so long as the 
proper temperature is maintained in the boiler. The ammoniacal vapor 
which leaves the refrigerator is redissolved to form the rich solution 
which is to supply the boiler j and the water of solution is the same 
which was previously withdrawn exhausted from the boiler itself. Thus, 
as there is nothing added to the contents of the apparatus, and as there 
is no escape of any part of them by leakage or otherwise, the same ma- 
terials go on indefinitely producing a uniform effect, the measure of 
which is expressed by the number of calories which the apparatus is 
capable of absorbing in an hour. Mr. Carre constructs five models of 
this form. The power of the smallest of these corresponds to an ab- 
sorption of twelve hundred calories per hour, and that of the largest 
to one of twenty thousand calories. The space occupied by the several 
parts of the apparatus is, for the smallest, twelve square metres (one 
hundred and thirty-two square feet;) and that required by the largest 
fifty-five square metres, or nearly five times as much. The boiler required 
for the smallest is about one metre high and thirty centimetres in 
diameter For the largest, the corresponding dimensions must be two 
and a half metres in height and eighty centimeters in diameter. The 
cost of the largest, packed and delivered in Paris, with all the accessories 
complete, is thirty-six thousand francs, and of the smallest about seven 
thousand. The largest will produce two hundred kilograms per hour 
and the smallest twelve. The first requires the labor of three atten- 
dants and the other of only one. 



CONTINUOUS FREEZING APPARATUS. 377 

Iii order that this ingenious and somewhat complicated apparatus may 
be better understood, the following description of its several parts is 
presented in detail. 

Plate VI contains a representation of the apparatus, taken for Mr. 
Ponillet in the workshop of the constructor. This apparatus was de- 
signed to produce one hundred kilograms (two hundred and fourteen 
pounds) of ice per hour. In this plate Fig. 1 represents the front eleva- 
tion, and Fig. 2 is an end elevation. Fig. 7 gives the view from above 
and furnishes an idea of the plan. Figs. 3, 4, 5, and 6 represent on a 
much larger scale, but still only about one-eighth of the actual size, the 
most important subordinate details. In both the elevations and in the 
plan the same letters are constantly used for the same parts. 

The boiler containing the aqueous solution of ammonia is distinguished 
by the letter A. It is exposed to the heat of the furnace B to about one- 
half its vertical altitude. The solution should never stand higher than 
this; and at is placed an indicator to show its exact level. This 
indicator is simply a glass tube placed vertically, and communicating 
with the boiler both at top and at bottom. 

At the summit of the boiler is a tube extending upward, with a branch 
through which the liberated ammoniacal gas is conducted to the large 
liquefier J. Above the branch, the tube is contracted, and at the top it 
carries a safety-valve with its lever and weight. If at any time this 
valve is lifted, the ammonia, instead of escaping in the air, is forced to 
pass down through the small pipe E into a vessel containing w^ater, E 7 . 
At F is seen the tube which feeds the boiler with the saturated solution 
of ammonia brought back from the absorbing apparatus ITU, to be 
presently described. 

The upper h ilf of the boiler G G, is occupied by a contrivance called 
the rectifier, w T hich consists of a series of broad and shallow vessels, 
pierced with holes in the manner of sieves, through which the solution 
introduced through F falls in a trickling shower till it finally reaches 
the mass of the liquid in the boiler. Each alternate basin has a large 
opening, H, in the middle, but extends at its circumference so as to meet 
the walls of the boiler in which it forms a partition. The intervening 
basins are free at their circumferences but without central opening, and 
are suspended from those above them. The object of this is to expose 
many times successively the ammoniacal gas arising from the solution 
in the boiler to the shower produced by the trickling from basin to 
basin of the liquid introduced by F. This takes place necessarily as 
the gas passes alternately from centre to circumference and from cir- 
cumference to centre in rising. The effect is to free the gas in great 
measure from the watery vapor which accompanies it at first ; this vapor 
being almost entirely condensed by the liquid which it encounters, and 
which is at a much lower temperature than itself. A secondary advan- 
tage is gained also by this arrangement, in that the liquid which enters 
through F at a temperature comparatively low, say 70° C, receives from 



378 PARIS UNIVERSAL EXPOSITION. 

the vapor which it condenses a large accession of heat, and to the same 
extent reduces the charge upon the furnace. 

The gas thus freed from vapor passes, as stated above, through the 
tube I to the liquener JJ, which consists of a combination of numerous 
zig-zag and spiral tubes immersed in a tank of cold water; the water 
being constantly renewed from an unfailing source in communication 
with Z, which is a distributing recipient designed to supply different 
parts of the apparatus. At the point where the tube I meets the 
liquener there is a kind of box, K, into whicli I opens, and from which 
there proceed three distinct tubes, which, after making four or five 
turns in the refrigerating water of the tank, terminate in a correspond- 
ing box, K 7 , at the bottom. Arrived at K' the gas will be reduced to a 
temperature of 20° to 25° C— say 70° to 80° F— and under the pres- 
sure of ten atmospheres, more or less, which is constantly maintained 
in the boiler, it is at this temperature reduced to a liquid state. In 
this condition it passes through the tube L to the vessel M, which is 
the regulator of efflux. This is a very important part of the apparatus. 
It forms the dividing barrier between the space in which there pre- 
vails a constant pressure of ten atmospheres and another where the 
entire efficacy of the contrivance depends on the maintenance of a pres- 
sure greatly lower, which, in fact, shall never exceed an atmosphere and 
a half. And while doing this it must at the same time permit the liquid 
ammonia to flow freely from the first of these spaces to the second, and 
prevent it from flowing more rapidly than the successful conduct of the 
operation requires. To understand in what manner and how simply it 
effects all this, attention must be turned to Fig. 6. This figure repre- 
sents a strong air-tight cylinder of cast iron of about eight inches in inter- 
nal diameter and fourteen in internal height. Within this is a hollo w cylin- 
der, n, made of very thin metal, so as to be buoyant. This is open at top 
but closed at bottom. The external cylinder has a prolongation down- 
ward in the direction of its axis, being in form a tube of about one inch 
in diameter. Toward the lower extremity of this prolongation, the inte- 
rior bore is reduced and made very truly cylindrical. The inner cylinder 
has a similar prolongation of less diameter, which at the lower extremity 
is enlarged and turned so as accurately to fit the reduced portion of the 
outer tube. The accuracy of this joint is important. It ought to be 
tight enough to prevent the escape of a liquid through it, but should 
not obstruct movement by excessive friction. The internal cylinder is 
maintained in a vertical position, free of contact with the outer oueJby 
means of a central guide represented at the top ati>, which is fixed to a 
bar crossing the mouth of the cylinder. This cylinder is represented 
in its lowest position resting on a studjp' at the bottom of the small pro- 
longation. In this position it will be seen that a perforation made 
through the walls of the joint just spoken of forms a communication 
between the tube m' and the interior of the cylinder. But if the inner 
cylinder be lifted slightly, the perforations in the two parts of the joint 



CONTINUOUS FREEZING APPARATUS. 379 

will cease to correspond and communication between m' and the interior 
will be cut off. 

The tube m at the top of the apparatus is the tube which is connected 
with L coming from the liquefier. It is here that the liquid ammonia 
flows in. There is a little plate or fender fixed to the inner cylinder at 
o opposite the tube m, the design of which is to prevent the liquid from 
flowing immediately into the inner cylinder and to direct it into the 
space between the two. In consequence of this arrangement the light 
inner cylinder will presently be buoyed up by the iuflowing liquid and 
will rise so as to obstruct, as just described, communication with mJ It 
is prevented from rising further than is necessary for this purpose by a 
stop represented on the guide p. As the influx of liquid from m con- 
tinues, the annular space between the two cylinders will presently be 
filled up, and the liquid overflowing into the inner cylinder will soon after so 
increase its weight that it will once more settle into the position repre- 
sented in the figure. There will then be a discharge through m'. Should 
the discharge be more rapid than the supply, and should the inner ves- 
sel maintain permanently this lower position, there would arrive presently 
a moment when all the liquid having passed, the uncondensed gas would 
begin to enter the refrigerator 5 an occurrence which would vitiate the 
result. There would arise at the same time the more serious danger 
that the pressure existing on the side of the boiler would be established 
in the refrigerator also. But these evils are prevented by the automatic 
action of the apparatus ; for so soon as the level of the liquid in the 
inner cylinder has descended about half way, the vessel becomes too 
buoyant to preserve its position. It therefore rises and shuts off com- 
munication with m' a second time. It will be seen that the guide p 
must be so constructed as not only to maintain the inner vessel in the 
vertical position, but also to prevent its rotation; and it will be quite 
evident that the inequality of pressure in the two spaces between which 
this joint is interposed cannot sensibly interfere with its action. 

The liquid having left the regulator through the pipe m', passes by 
the tube N to the cavity P, which is called the distributor. On its way 
this tube is conducted through the enveloping tube O, the use of which 
will be explained further on, but which is not an indispensable part of 
the apparatus. This enveloping tube is wound round the tube T, 
through which the vaporized ammonia is returning from the refrigera- 
tor QQ. These vapors, being very cold, serve to reduce the tempera- 
ture of the liquid in N, before it enters the refrigerator. 

The refrigerator itself consists of a number of zigzag or spiral tubes — 
in the apparatus here represented, six in all — immersed in a tank con- 
structed of non-conducting substances. These zigzags return upon 
themselves six times, forming so many partitions in the tank, between 
which vessels containing the substances to be subjected to cold may be 
placed. Each one of the six zigzags receives an equal supply of the 
liquid ammonia from the distributor. The small tubes conveying this 



80 PARIS UNIVERSAL EXPOSITION. 



supply are shown at P, in Fig. 1. The vessels to be refrigerated are 
sustained by a kind of carriage or slider, which admits of a reciproca- 
ting motion, and which receives this motion from the same machine 
which works the pump employed to return the resaturated solution of 
ammonia to the boiler. Fig. 7 shows this connection, and tlie manner 
of the movement. In this figure the vessels containing the substances 
to be frozen are marked E. The arrangement of the same vessel as seen 
from the side is shown under the same letter in Fig. 1. In the same 
figure is seen, at the bottom of the refrigerator, the large tube S. into 
which all the zigzags. E, discharge the vaporized ammonia. The whole 
space in the tank surrounding the zigzags and the vessels marked E is 
filled with an incongealable liquid, which may be alcohol, but is usually 
a solution of chloride of calcium. 

From S. which is called the collector, is seen rising the tube T. which 
conveys the gaseous ammonia to the cylinder U. passing by the way 
through the enveloping tube O, where it receives some heat from the 
liquefied gas which is passing through X to the refrigerator. This vessel 
U is ordinarily partially filled with water drawn from the bottom of the 
boiler, from which the ammonia has been in great part exhausted, aud 
which is therefore ready to take up greedily the gas introduced through T. 
The tube T. as is seen in the figure, extends nearly to the bottom of the 
vessel, and delivers the gas beneath the surface of the water. At U, on 
the left, is an indicator of water level, similar to that at C. Within this 
vessel U is observed a spiral tube. Through this spiral there circu- 
lates a current of cold water, entering by the tube a. which extends 
from the reservoir Z to the lower extremity of the spiral, and passing- 
out through the tube b 7 which discharges it into the vessel Y. Xear 
the top of the vessel there is seen also a flat vase V. This is designed 
to receive the absorbing water brought from the boiler : and its bottom 
is pierced with holes like those of the vases of the rectifier GG. that the 
water may fall through in a shower, and thus present to the gas a greater 
absorbent surface. 

The water is not brought, however, from the boiler directly to IT. In 
that case it would be too hot to absorb the gas effectually. It passes 
first through the two coolers X and Y. Into X it is introduced through 
the tube W, by turning the cock shown at W. The pressure in the 
boiler expels it without necessitating the use of a pump. The stop-cock 
may be set so as to supply very accurately the water in proportion as it 
is wanted. The vessel X is formed of two concentric cylinders, and 
between these are two spiral tubes, formed of the tube TT continued, and 
conveying the water drawn from the bottom of the boiler. These spirals 
are immersed in a liquid filling the annular space between the cylinders, 
which is the reconstituted ammoniacal solution on its way from the 
absorber to the boiler. The water from the boiler is hot. and the solu- 
tion from the absorbent is cold. The two liquids to some extent 
exchange their temperatures by this contact: and this is. so far as it 



CONTINUOUS FREEZING APPARATUS. 381 

goes, an economical ad vantage in both ways. It promotes this exchange 
that the two fluids circulate in opposite directions ; the liquid from the 
absorbent entering at the bottom and ascending, while the heated water 
from the boiler enters at top and descends. From X, the water from 
the boiler is conveyed in the tube W, still continued, to the vessel Y, 
where it forms but a single spiral ascending from the bottom to the top, 
and is refrigerated by the water discharged from the spiral in TJ, which 
enters Y by means of the tube b. It reaches, finally, by the tube W, 
still continued, the absorbing vessel U, being received in the vase V, 
and descending through its perforated bottom in a shower, as above 
described. 

It has been stated that the exhausted water is drawn from the boiler 
through the tube W, and that the saturated solution from the absorbent 
is returned through the tube F. The water flows freely, on merely turn- 
ing the stop-cock W, but some force is required to drive the solution 
back through F. This force is supplied by a pump g, operated by a 
small steam-engine or other source of power. To prevent any escape of 
ammoniacal gas from the pump some special provisions are necessary. 
Such an escape would be not only economically disadvantageous, but 
would be attended with unpleasant effects to the attendants. The form of 
the pump employed is shown in Fig. 4, which is drawn to a scale one-eighth 
of the actual dimensions. In this figure the tubulure u is that through 
which the saturated solution is drawn from the absorbent by means of 
the tube marked h in the general view of the apparatus ; and the tubu- 
lure u' is that by which it is forced through the tube i (best seen in the 
drawing in plan) into the annular space of the vessel X, and from that 
through F into the boiler. A tube of caoutchouc, marked v in the sec- 
tion of the pump, is secured firmly to the upper part of the piston (which 
is reduced in diameter for the purpose) by means of an iron binding- wire, 
and surrounds the piston rod, as far as the top of the barrel, where it is 
turned over and fastened by a plate bolted on as shown. Any gas 
which might make its way between the packing of the piston and the 
barrel will thus be prevented from escape at the top, while the elasticity 
and flexibility of the tube will allow perfect freedom of motion. A sec- 
ond tubulure u" communicates with the upper part of the absorbent X, 
through the tube h', and thus prevents any accumulation of gas above 
the piston. 

Stop-cocks are employed to close at pleasure the principal communi- 
cating tubes of the apparatus. These are protected against leakage in 
a similar manner. Fig. 3 is a section of one of them. The core of the 
stop-cock is conical, as seen at q, and it is kept firmly in place by means 
of a spiral spring in a cavity beneath it, which cavity is closed by a screw 
with caoutchouc packing. A tube of caoutchouc surrounds the stem of 
the stop cock, which is of some length, and this is bound at the bottom 
by means of iron wire to a short tube rising from the bulge of the stop- 
cock of which it forms part, and to the enlarged upper end of the stem 



382 PAEIS UNIVERSAL EXPOSITION. 

also. This tube is surrounded and protected by a succession of iron 
rings t /, which strengthen it against interior pressure, but allow the 
stein freely to turn so far as to open and close the cock. Stop-cocks 01 
this kind are placed in the tubes F, W, and IS", and a larger one in T. 

Fig. 5 represents the distributor P, and is designed to exhibit the 
manner in which the supply is equalized to the several zigzags of the 
refrigerant. The letter w here marks the junction of the distributor 
with the tube £T, which introduces the liquefied ammonia from the reg- 
ulator M. The liquid descends through the tube w' to the bottom of the 
distributor. The tubes x x a?, which rise vertically through the bottom 
of the vessel, are in communication with the several branch tubes lead- 
ing to the zigzags, and each of these is perforated with similar holes at 
equal heights, permitting all to receive equal portions of the liquid as 
it reaches the common level. 

One or two observations further only are necessary. TVTien the 
operation begins, the whole apparatus is necessarily full of air. This is 
expelled by means of a simple contrivance called a purger. The purger 
is a cylindrical vessel partially filled with water, shown at d, into which 
descends a tube c, from the absorbent U, closed ordinarily by a stop- 
cock. At the commencement of the operation, the boiler having been 
charged with a strong solution of ammonia, the cocks are all closed until 
the temperature of the solution has reached 130° or 140° C, when free 
communication is established between the different parts of the appara- 
tus, and the cock leading to d is also opened. The gas expels the air 
through the tube c beneath the surface of the water in d, from which it 
escapes in bubbles, while the ammonia is retained in solution by the water 
and may be recovered. 

The tubes e/are parts of the apparatus not indispensable. The first 
of these serves to conduct water from the general reservoir Z to the 
large envelope O of the tubes X and T, and the second is movable, and 
serves conveniently to fill the vessels E with water designed to be frozen. 
It is an advantage that this water, in passing through the enveloping 
tube O, (which for this purpose should have considerable capacity, and 
should be secured water-tight at its extremities to the tubes passing 
through it,) will have its temperature considerably depressed in advance 
by the effect of the cold vapor returning through T. 

When the apparatus is constructed upon a smaller scale some of its 
parts are more simple. If, for instance, there be but one zigzag or spiral 
in the refrigerator, the distributor may be omitted, and the liquefied 
ammonia may be conveyed directly from the regulator to the refrigerator. 

It need hardly be observed that, after this apparatus has been some 
time in action, there will be found to have accumulated in the collector S 
a certain amount of water or ice, formed of the watery vapor which 
passes over from the boiler along with the ammonia, and which remains 
behind in the refrigerator because of its inferior volatility. This is from 
time to time removed by means of suitably arranged stop-cocks. 



COST OF ICE ARTIFICIALLY PRODUCED. 383 

It will be seen that this apparatus requires a large amount of refrige- 
rating' water to maintain at the desired temperature the liquefier and 
the absorbent vessel, and that it also requires a consumption of fuel, not 
only to beat the boiler containing the ainmoniacal solution, but also to 
work the forcing pump. The pump may be worked by water power, if 
such a power is obtainable, or even in small models by hand; but for an 
apparatus producing more than fifty kilograms of ice per hour, a 
motor is indispensable. 

It is stated by Mr. Carre that for every kilogram of coal burned 
there are produced from eight to twelve kilograms of ice, according 
to the dimensions of the apparatus. To manage the larger forms of the 
apparatus, the services of two men are required, and a motor also is 
necessary, capable of driving eight hundred and forty litres of liquid per 
hour into the boiler. The pressure in the boiler must be taken, for the 
purposes of computation^ at not less than ten atmospheres ; and as the 
machines are adequate to the production of two hundred kilograms 
per hour of ice, they will, within the same time, liberate from solution, 
liquefy, evaporate, and redissolve forty kilograms of pure ammonia. 
These data may enable us to calculate the probable cost of production, 
supposing such an apparatus to be set up in this country. 

First, as to the expenditure of heat in the furnace. The forty kilo- 
grams of ammonia, with the twenty times forty of water, which are 
required to dissolve it, give a total of eight hundred and forty kilograms 
of liquid to be acted upon. At the beginning of the operation this liquid 
may be at 17° of temperature, but as, after the mass has once been 
heated up to the working point, the supplies which return to the boiler 
are probably never below 60° C, we may consider that for continuous 
work we have to heat eight hundred kilograms of water from 60° C 
to 130° 0, that is to say, through a range of 70°, and also to convert 
forty kilograms of liquid ammonia, at the temperature of 60° O, into 
vapor at 130o O. 

The furnace must then furnish to the water fifty-six thousand calories; 
to the ammonia, in the form of latent heat, twenty thousand; and in the 
form of sensible heat, one thousand four hundred ; in all seventy-seven 
thousand four hundred calories. This wordd require the combustion of 
thirteen kilograms of coal, capable of producing six thousand calories the 
kilogram, which, at three and a half centimes the kilogram, would cost 
less than half a franc, or about nine cents. At eight dollars a ton the 
same amount would cost ten cents and a half. The actual consumption 
would be considerably greater, but in long-continued operations, and in 
furnaces carefully constructed with a view to economy of heat, it need 
not be more than doubled. Supposing an actual consumption of twenty- 
five kilograms per hour, each kilogram will produce eight kilograms of 
ice; a result which corresponds with the lower limit fixed by Mr. Carre. 
Different kinds of fuel differ so much in their heating power that an 
estimate of this nature cannot be made exact without knowing the 



384 PARIS UNIVERSAL EXPOSITION. 

description of fuel to be used. If the coal furnishes seven thousand five 
hundred calories per kilogram, the production will rise to ten kilograms 
of ice per kilogram of fuel. And possibly a severe attention to economy 
in the arrangements of the furnace may effect a sufficient saving of heat 
to justify Mr. Carre's highest statement. 

To the cost of the coal for the boiler is to be added that of the fuel for 
the motor. This may be estimated by considering the work to be done. 
Eight hundred and forty kilograms per hour are to be injected into the 
boiler, against a pressure of ten atmospheres ; which, at ten metres to 
the atmosphere, is equivalent to raising the same weight to a height of 
one hundred metres. The total work thus performed is equal to eighty- 
four thousand kilogram metres per hour, which is about one-third of a 
horse-power. If we make the force of the motor, for security, half a 
horse-power, there will be required about a kilogram of coal per hour, 
practically, perhaps, something more, to keep it in operation. The con- 
sumption of fuel on all accounts, per hour, will not exceed, therefore, 
fourteen kilograms ; and if the coal is of superior quality, may fall as 
low as eleven, at a cost of from nine to twelve cents. 

The principal item of current expense in this manufacture will be, 
however, the wages of the attendants. Two attendants, competent to 
manage an apparatus of so peculiar a description, could hardly, in this 
country, be obtained for less than five dollars a day. If the working 
day extend to ten hours, the cost of attendance will then be fifty cents 
an hour. 

Two hundred kilograms of ice will thus be obtained with an outlay of 
not more than sixty-two cents, or seven pounds avoirdupois for one cent. 

This result keeps out of view, however, the interest on the investment, 
and the incidental expenses for repairs, for lubricants for the motor, and 
other minor matters. The influence of these considerations may be 
appreciated by taking into view the operations of an entire year. If we 
suppose the apparatus to operate ten hours every day, and three hun- 
dred days in the year, the total production will amount to six hundred 
thousand kilograms of ice per annum. Attendance, at five dollars a day. 
will cost fifteen hundred dollars per annum. Coal, at one dollar and 
twenty cents per day, will come to three hundred and sixty dollars per 
annum. The apparatus, if purchased in Paris and imported without 
duty, would cost, in currency, ten thousand dollars, and. with the duty 
on, probably fifteen thousand dollars; on which sum the annual interest. 
at six per cent., would be nine hundred dollars. If the manufacture were 
attempted in a city there would be a serious item for rent. We may 
suppose it to be so situated that the expense on this account need not 
exceed one hundred dollars a year. These sums united amount to two 
thousand eight hundred and sixty dollars 5 and if we allow one huudred 
and forty dollars for incidental expenses not included in the foregoing. 
we shall have a total outlay of three thousand dollars to produce six 
hundred thousand kilograms of ice. This is equivalent to a cent tor two 
kilograms, or a quarter of a cent a pound avoirdupois. 



ECONOMY OF CARRES' ICE APPARATUS. 385 

It is presumed in what lias been said thus far, that the water, which 
will be required in pretty large volume to absorb the heat given out 
during the liquefaction and the re-solution of the gaseous ammonia, will 
be obtainable without cost. But this is a supposition which cannot be 
made unless the apparatus is established at some point below the level 
of an adequate natural source to which no commercial value is attached. 
If the water has to be elevated by mechanical means, or if it is derived 
from the public water supply of cities, it will constitute an additional 
item of expense which will have to be taken into account. 

The quantity of water to be provided may be calculated as follows : 
In the liquefier the gas is received at 130° C, and the liquid is delivered 
at 25° C. Its sensible heat has to be reduced 105°, and all its latent 
heat absorbed. The first of these items amounts to two thousand one 
hundred calories, and the second to twenty thousand calories; in all, 
twenty-two thousand one hundred calories per hour. Supposing the 
water of refrigeration to be received at 17° C, and discharged at 25° 0, 
every kilogram will carry off eight calories, and the removal of all the 
heat will require two thousand seven hundred and sixty-three litres. 

In the reunion of the evaporated ammonia with the exhausted water 
drawn from the boiler, there is a demand for a still larger supply of 
water of refrigeration. The water is drawn from the boiler at the tem- 
perature of 130°, and the solution is effected at that of 25° 0. The water 
on its way to the absorbing vessel exchanges temperatures, to a certain 
extent, with the regenerated ammoniacal solution. Their difference of 
temperature is one hundred and five degrees. It is hardly supposable 
that they reach the common mean. If we suppose that each approaches 
the mean by one-third of the difference, we shall probably be not far 
from the truth. The heated water will then enter the refrigerating ves- 
sel at a temperature of 95° 0, and this must be reduced to 25° ; that 
is to say, through a range of seventy degrees. Eight hundred kilo- 
grams, in falling seventy degrees, will liberate fifty- six thousand calories, 
which must be taken up by the surrounding water. The ammoniacal 
vapor coming from the refrigerator will give up, in entering again into 
solution, its twenty thousand calories of latent heat. This vapor leaves 
the refrigerator at perhaps — 15° 0, but it partially exchanges tempera- 
tures with the liquid ammonia which is on its way to the refrigerator at 
the temperature of 25° 0. The liquid possessing more than twice the 
capacity for heat which belongs to the vapor, the former probably de- 
scends to fifteen degrees in consequence of the i>artial exchange, while 
the latter may rise to five degrees, and at this temperature is delivered 
into the absorbent vessel. In rising to twenty-five degrees it absorbs 
four hundred calories, which are to be deducted from the sum of the two 
preceding numbers. Uniting these results, we find that provision must 
be made for the removal of seventy-five thousand six hundred calories 
during the regeneration of the ammoniacal solution. And supposing, 
once more, that the water employed to convey away this heat does not 
23 i A 



386 PARIS UNIVERSAL EXPOSITION. 

gain in temperature more than eight degrees, the total volume required 
will be nine thousand four hundred and fifty litres. This, being added 
to the two thousand seven hundred and sixty- three litres required for 
the liquefaction, will give a total of twelve thousand two hundred and 
thirteen litres — say, in round numbers, twelve thousand — or three thou- 
sand two hundred English wine gallons required per hour, which is 
equivalent to a constant influx at the rate of nearly a gallon per second. 
It is evident that the economy of the process will be sensibly affected by 
the question of water supply. 

The production of ice is not the only practical application of the cold- 
generating apparatus of Mr. Carre. There are many industrial processes, 
which for their success depend upon the maintenance of a moderately 
low and steady temperature ; and others which are greatly promoted, or 
which succeed, only when the depression of temperature is extreme. In 
breweries, and in manufactories of sugar, we have examples of the first 
class of these applications; and in the concentration of saline or alco- 
holic solutions, in the crystallization of certain salts, in the determina- 
tion of certain chemical reactions, and in furnishing more rapidly than 
it can be done by distillation, fresh water from the ocean at sea, the 
second is illustrated. But the amount of useful effect which can be 
obtained from a given apparatus will not be the same in all these varie- 
ties of application. This is owing to the varying amount of loss which 
occurs under different circumstances, but which occurs to a greater or 
less degree in all. Moreover, where surrounding circumstances remain 
the same, the amount of loss will be in a measure dependent on the 
intensity of the cold which it is desired to produce. In the manufacture 
of ice, the vessels containing the product may be removed as soon as the 
congelation is complete ; but if, for any purpose, it is sought to produce 
ice of a temperature of ten or fifteen degrees below zero, there will be an 
increased liability to the invasion of the apparatus at this lower tem- 
perature by heat derived from the surrounding air. It is evident that 
if the ice were not removed at all, and the apparatus were to be main- 
tained in activity for an indefinite time, there would arrive a moment 
when the accession of heat from without, always increasing as the depres- 
sion continues in the refrigerator, would just balance the amount with- 
drawn by evaporation, always diminishing with the same depression. 
At this point the useful effect of the machine would practically cease. 
What would be the extreme limit of cold which, under such circum- 
stances, the apparatus would reach, cannot, perhaps, be exactly stated. 
It would depend very much on the temperature prevailing in the apart- 
ment in which the operation is conducted, and on the relative proportions 
of the boiler and the refrigerator 5 but in an atmosphere at zero, it might 
descend to sixty or seventy degrees below. 

EXTRACTION OF POTASH FROItf SEA WATER BY EEFERtEEATKEn. 

The useful applications which have been thus far made or suggested of 
the apparatus do not, however, require so extreme temperatures as this. 



EXTRACTION OF POTASH FROM SEA-WATER. 60 I 

One of the most important of these has been to the extraction of vain- 
able salts of soda and potash from the mother waters left in the manufac- 
ture of common salt from the waters of the sea. In the evaporation of sea 
water by solar heat, the common salt, which is the most abundant of its 
saline ingredients, is at first deposited nearly or quite pure, and this con- 
tinues until about four-fifths of the entire amount has been withdrawn 
from the solution. In the mother water which remains, there is present 
a mixture of common salt with sulphate of magnesia, and the chlorides of 
magnesium and potassium. The separation of these salts has heretofore 
been a difficult operation, attended with large loss, and only partially 
effectual. The sulphate of magnesia and the chloride of magnesium are 
of little value, and their presence renders the treatment of the solution 
difficult. But if these waters are subjected to a temperature of 18° be- 
low zero, there takes place a double decomposition of common salt and 
sulphate of magnesia, with the formation of sulphate of soda which is 
deposited in crystals, and of chloride of magnesium which remains in 
solution. The sulphate of magnesia is thus almost entirely withdrawn 
from the water, and the sulphate of soda which is obtained, is a valuable 
commercial product j being the material from which carbonate of soda,, 
the most extensively useful of all chemicals in the industrial arts, is ordi- 
narily prepared. The waters are now subjected to evaporation over the 
fire, and the remaining common salt which they contain is deposited in 
the form of the most beautiful fine salt. The chlorides of magnesium 
and potassium still remain in the solution $ but when the concentration 
has reached the specific gravity 1.31, the solution is allowed to flow over 
a broad surface of beton, where, in cooling, it parts with all the potash it 
contains in the form of a double chloride of potash and magnesium. 
The remaining water, containing only chloride of magnesium, is rejected. 
This double chloride, washed with half its weight of cold water, yields 
three-quarters of its potash in the form of chloride of potassium ; and 
the remaining quarter, still held in solution in the water used in this 
final operation, is returned to the boiler. The separation of potash from 
sea water, thus effected, is one of the most important and valuable results 
which science has, in modern times, contributed to the industrial arts. 
Though potash is the most useful of the alkalies, the natural sources 
from which it is possible to obtain it economically are very few in num- 
ber. Hitherto the supply has been chiefly derived from the ashes of 
land plants, from which it is separated by lixiviation. This resource, 
which continually grows more precarious as civilization advances and 
as forests disappear, is destined, doubtless, to give way to the process 
just described, and which has already been for a number of years in 
active and successful operation in connection with the vast salines of 
Mr. Henri Merle & Co., at Giraud, on the Mediterranean coast of France. 
The salines of this company cover ten thousand hectares, (twenty- 
five thousand acres.) The company have applied the treatment above 
described to the mother waters derived from the tenth part of this area, 



388 PARIS UNIVERSAL EXPOSITION. 

amounting to one hundred thousand cubic metres per annum, with an 
annual product of four thousand tons of anhydrous sulphate of soda, one 
thousand tons of chloride of potassium, and twelve thousand tons of 
refined table salt. The amount of potash salt obtained bears but a small 
proportion to the other substances, but it is an exceedingly important 
contribution to the resources of the chemical arts. 

One great advantage attending this process is found in the fact that 
the condition of the waters after leaving the refrigerator is so changed 
as to prevent the formation of incrustations upon the interior of the 
boilers, a trouble which in all previous methods of treatment was 
exceedingly annoying, and sometimes interrupted the operation alto- 
gether. This is a consequence of the almost complete decomposition of 
the sulphate of magnesia during the refrigeration, and the removal of 
the sulphuric acid in the form of sulphate of soda, while the amount of 
chloride of magnesium is largely increased. It results that not only is 
there no formation of the heavy crusts which occur in the boiling of the 
waters which have not been subjected to this process, but even the 
slight incrustations which are formed in the refining of mineral salt are 
not at all seen. 

Having stated, just above, the total amount of the various salts which 
are annually obtained by the refrigerating process of Mr. Carre, as 
applied to the mother waters of the salines of Giraud, it may be worth 
while to estimate the cost of the operation. The waters are reduced in 
temperature to — 18° C ; and as the process is continuous throughout the 
year, it may be assumed that their initial temperature is as high as 
12° 0, perhaps 15° C. Adopting the latter number for the sake of the 
computation, and assuming that the specific heat of the saline solution, 
taken according to volume, is not essentially different from that of 
water, the refrigeration of every litre of the solution will require the 
removal of thirty-three calories. And as a cubic metre contains one 
thousand litres, the entire amount of heat to be abstracted from the one 
hundred thousand cubic metres will amount to the large total of three 
billion three hundred million calories. This amount requires still to be 
increased by ten per cent., since it is found necessary to dilute the solu- 
tion by one-tenth its bulk of fresh water, in order to prevent the deposit 
of common salt along with the sulphate of soda whieh it is the object 
of the refrigeration to obtain. Making the addition, it appears fiually 
that there are three billion six hundred and thirty million calories for 
the annual absorption of which provision must be made. This is equiv- 
alent to the heat produced by the combustion of six hundred and live 
tons of coal, taken at six thousand calories the kilogram. 

We have seen, however, in the discussion of the economy of the large 
apparatus of Mr. Carre above, that for every twenty thousand calories 
absorbed in the refrigerator, seventy-seven thousand four hundred must 
pass into the solution in the boiler; so that, allowing for waste by the 
chimney and otherwise, we must expect to expend in the furnace at least 



USE OF REFRIGERATING APPARATUS IN BREWERIES. 389 

six times as much heat as we remove in the refrigerator. It is neces- 
sary, therefore, to allow for a consumption of something like three 
thousand six hundred tons of coal, which, at thirty-five francs the ton, 
will cost one hundred and twenty-six thousand francs. 1 

There may he, however, a very large saving upon this, amounting to 
probably a third, effected by causing the exhausted fluid leaving the 
apparatus to exchange tenrperatures with the fresh solution entering ; 
and, moreover, this process is not to be charged with the entire cost of 
the fuel employed in it, but only with the excess of its consumption 
above that of the process which it has replaced, a point in regard to 
which information is wanting. 

It is probable that the cost of labor and attendance is substantially 
the same for both processes ; so that it may safely be assumed that a 
great part of the increased production is a clear profit. This increased 
production is probably more than half the total amount ; that is to say, 
it exceeds six thousand tons of refined table salt, two thousand tons of 
sulphate of soda, and five hundred tons of chloride of potassium per 
annum. Against -this we have to set off the increased expenditure on 
account of coal, which is probably but a small fraction of the total value. 

OTHER USEFUL APPLICATIONS OF REFRIGERATING APPARATUS. 

There are many other useful applications of the refrigerating appa- 
ratus of Mr. Carre, which it will suffice to notice briefly. In the first 
place may be mentioned its employment, which is likely soon to be gen- 
eral, in breweries, to preserve the must of malt from fermentation, or to 
maintain it during fermentation at a determinate but moderate tempera- 
ture. It is known that during the warm season the greatest care and 
attention are often insufficient to prevent great loss from the rapidity of 
change of the fermenting liquid. Many of the largest European brewing 
establishments have already introduced artificial refrigeration into their 
works with entire success and to their great advantage. 

The manufacture of sugar, whether from the cane or from beet-root, 
is attended with constant danger of loss from the great liability of the 
expressed juice to ferment, with the conversion of its suspended sugar 
into alcohol and carbonic acid. Slight elevation of temperature pro- 
motes this tendency ; a high heat along with defecating substances in 
great measure removes it, but is attended with another danger, viz : 
that of destroying its property of crystallizing. After the expression 
of the juice there is always more or less loss from the first of these 
causes, since the operation necessarily takes place in warm weather; and 

1 In regard to the proportion of useful effect to waste in the refrigerator, it ought, per- 
haps, to be here remarked that the present is one of those cases spoken of above, in which 
the exposure to loss of effective power is greater than the average, on account both of the 
large surface exposed to the air and of the low temperature to which the liquid mass has to 
be reduced. The estimate given in the text of the amount of fuel necessary, will therefore 
probably fall below the actual consumption. 



390 PARIS UNIVERSAL EXPOSITION. 

during the rapid evaporation which follows there is additional loss from 
the second cause. It is believed that both of these evils may be pre- 
vented by means of artificial refrigeration. In regard to the first there 
is no doubt ; as to the second it is not known how far the experiments 
which have been made have proved to be satisfactory. When an aque- 
ous solution of almost any kind is subjected to a freezing process, it is 
observed that congelation begins with the water only, and that the first 
ice which is formed contains but a minute quantity of foreign matter. 
The unfrozen portion of the liquid constitutes, therefore, a solution much 
more concentrated than the first. Xow, if from a dilute solution like 
that of sugar in the juice of the cane it is desired to be rid of the water, 
two processes present themselves ; the water may be expelled by heat in 
the form of vapor, or withdrawn in the form of ice by the aid of cold. 
If this last process succeeds without withdrawing at the same time any 
important proportion of the substance in solution which it is desired to 
save, it will be on several accounts a preferable process. For, in the 
first place, it will be a security against loss from the decompositions 
which occur spontaneously at higher temperatures 5 and secondly, it will 
require only about one-sixth part as much fuel to remove a given quan- 
tity of water from a solution in the form of ice, when used in Carre's 
apparatus, that is necessary to convert the same water into steam, and 
thus to remove it by evaporation. The method of refrigeration is, more- 
over, free from the danger of in any manner impairing the property of 
crystallization. Should it be found that it does not remove along with 
the water a serious amount of the sugar in solution, this process cannot 
fail to be a valuable auxiliary in this very, important manufacture. 

The same process has been employed advantageously in improving the 
quality of wines by concentration, and it is obvious that it is similarly 
applicable to alcohol; to acids, and to aromatic principles, which are ordi- 
narily separated with injury and loss by distillation. 

In the transportation of supplies for the daily markets of large towns, 
the refrigerating process is destined in the future to be productive of 
great public benefit. At the present time, cattle, sheep, and fowls are 
conveyed in vast numbers in closely-packed cars, and in the most sultry 
weather, for long distances to the points at. which they are to be slaugh- 
tered for food. Owing to the suffering to which they are subjected, they 
often reach their destination in lamentable condition. Hot unfrequently 
they are found to be sensibly reduced in their weight by fatigue and 
insufficient feeding during their transportation: and it would not be too 
much to affirm that in many cases they fail to arrive in such a state of 
health as to make their flesh an entirely wholesome food. All these 
evils would disappear if the animals could be prepared for food at the 
points where they are raised, and transported to their destination in 
form to be delivered directly to the consumers. And the additional 
advantage would be gained that the bulk and weight of the mass to be 



REFRIGERATING APPARATUS FOR COOLING APARTMENTS. 391 

transported would be reduced more than one-half. On grounds of 
humanity, of economy, and of the sanitary interests of the public, such 
a change, if practicable, is greatly to be desired. In countries where 
ice is naturally formed in great abundance, there is no reason why 
refrigerator cars should not be attached to market trains upon our rail- 
roads, and kept at a temperature near to zero by a liberal use of this 
naturally formed ice. It has been suggested that a still more effectual 
mode of accomplishing the object which this arrangement would be 
intended to secure, and which, in some instances, it has been actually 
employed to secure, would be first to reduce the temperature of the 
meat to be preserved by exposing it for a short time in the apparatus of 
Mr. Carre, to a temperature about three or four degrees below 0° C, and 
then, after withdrawing it and enclosing it in a vessel or an envelope 
impervious to water, to immerse it in the same apparatus, and by a con- 
tinuation of the process to enclose the whole in a solid block of ice. 
This might be too elaborate a mode of preservation for the entire sup- 
ply of a large city market, but for delicacies and articles which have to 
be transported to great distances it would be well worth adopting. 
The ice-envelope might be reduced in temperature some degrees below 
zero, and, placed in a proper refrigerating car, it would long continue to 
be a perfect protection. 

The ventilation of churches, theatres, and all public assembly rooms, 
during the warm season, is another object to which the refrigerating 
apparatus of Mr. Carre may be made very beneficially subservient. It 
is now generally true that during the warm days of summer the outer 
air is at a higher temperature than that within the building; and this 
will invariably be the case in structures of masonry, provided the win- 
dows be kept open during the night, and are closed at sunrise. Not- 
withstanding this, a crowded assembly will find it intolerable in summer 
to sit in an apartment where there is no movement of air. The windows 
will be thrown open, the warm air admitted, and the assembly will be 
more uncomfortable than before. Nothing is easier, however, than to 
introduce into any such apartment a steady flow of air at a temperature 
of refreshing coolness, by which the hot air shall be expelled and a per- 
manently comfortable atmosphere substituted. To accomplish this 
desirable object it will not generally be necessary to provide any 
special system of distribution for the cool air introduced. Our public 
buildings are, in most cases, already provided with ducts for conveying 
heated air in winter from furnaces to their several apartments, and the 
same channels will serve in summer for air artificially cooled. It will 
evidently be no less easy to control, by means of registers, the degree 
of depression of temperature in the apartments than it is in the oppo- 
site season to regulate the heat. A s to the means of transferring to 
large bodies of air the cold pro U ced by the refrigerating apparatus, 
they will easily be devised, and may U ke a variety of forms. A refrig- 



302 PAEIS UNIVERSAL EXPOSITION. 

erator may be constructed, for instance, on the general plan of that 
shown in Plate VI, only having the spa ;es designed for the chloride of 
calcium solution much narrower and perfectly free. Through these, air 
may be driven in a perpetual stream by any usual ventilating fan. To 
prevent any ill effects from cold draughts in a room occupied by a large 
assembly, the discharge may b i made near t e ceiling, and the air first 
delivered into a large receiver, from which it m L y ( scape into the room 
through considerable surfaces of wire gauze. 

There is still another useful application o : ' the process of artificial 
refrigeration in the preparation, on a large scale, by crystallization, of 
many soluble salts. There are few salts whose so ubility is not greatly 
increased by heat, or which are not to a very large extent, if not entirely. 
deposited under the influence of extreme cold. Salts which in their 
solutions would require great concentration in order to effect their crys- 
tallization at ordinary temperatures, crystallize at once when the 
temperature - is considerably depressed; and where a manufacture of 
this kind is conducted on a large scale the operation may be made con- 
tinuous, and considerable economy may be secured by causing the 
exhausted water, on leaving the refrigerator, to exchange temperatures 
with the saline solution which is entering. 

Besides the cold-producing contrivances in which the efficient agent is 
liquefied ammonia, Mr. Carre has constructed machines for accomplishing 
the same object by means of volatile substances which retain their liquid 
form under the ordinary pressure of the atmosphere, such as ether. In 
these, of course, the vapor formed in the refrigerator must be removed 
by mechanical means, as it is impossible to absorb it. either economically 
or expeditiously, as is done in the case of ammonia, by means of any 
solvent. A powerful air-pump is employed, acting at once as an 
exhausting and a compressing-pump, for the purpose of maintaining a 
low pressure in the refrigerator, and driving the vapor at the same 
time into a condensing vessel, where it is made to resume its liquid form, 
and where it yields up its latent heat to the water in which the con- 
denser is immersed. These machines were not exhibited by Mr. Carre, 
and are, perhaps, no longer constructed by him. The ammoniacal 
apparatus offers advantages greatly superior, as will be obvious when 
it is considered that the latent heat of ethereal vapor is less than the 
fifth part of that of ammoniacal gas, while its density is more than four 
times as great ; the specific gravity of the two in the liquid state being 
nearly equal. The specific gravity of ether is 0.72. and that of liquid 
ammonia 0.76. From these data we compute that in order to produce 
any determinate effect, to remove, for instance, a thousand calories, a 
bulk of ether would be necessary nearly five and a half times greater 
than would be required of ammonia for the same purpose. Thus, in 
order to absorb one thousand calories, it would suffice to evaporate 
something less than a litre and a half of ammonia : but if ether is sub- 



CARRES ETHER APPARATUS — TELLIER S^APPARAT LIS. 393 

stituted, more than eight litres will be necessary. The ether apparatus 
of Mr. Carre is nevertheless very in >■■ nious, especially his very effectual 
contrivances for preventing the possibility of the slightest leakage 
through stop-cocks, joints, or stuffing-boxes. 

The ether employed by Mr. Ca re is the or Unary ether of commerce. 
Methylic ether, or the ether of woo - it ^s been used or the same 
purpose by another inventor, Mr. Charles Tellier, who has constructed 
refrigerating apparatus for breweries, and for cooling the air of apart- 
ments. Though Mr. Tellier's name appears in the list of exhibitors, his 
apparatus was not present in the Exposition. It is understood, how- 
ever, to be constructed on principles quite similar to those of the ether 
apparatus of Mr. Carre. Methylic ether has the advantage over the 
ordinary ether, called sulphuric, in b3ing greatly more volatile. It 
exists under the ordinary temperature and pressure of the atmosphere 
only in the gaseous state, and becomes liquid without increase of pres- 
sure at — 24° C. At 20° C it requires about four atmospheres for its 
liquefaction. Mr. Tellier's apparatus was originally constructed with a 
view to its use on shipboard as a means of obtaining fresh water from 
the waters of the sea, but it is equally applicable in any situation and 
to any purpose for which refrigeration is required. It will produce a 
greater intensity of cold than ordinary ether, and, other things being 
equal, will operate more rapidly 5 but it requires, also, a much more 
powerful pump for withdrawing the vapor from the refrigerator and 
compressing it into the condenser. In the case of common ether, this 
pump has to work against a pressure of only one atmosphere 5 with 
methylic ether, it must be capable of working against four at least. 
The machine of Mr. Tellier has been introduced successfully into the 
great brewery of Bass & Co., at Burton, in England. 

Among the contrivances for odu ' cold artificially, should not be 
forgotten those which have been from time to time introduced into tem- 
porary use, deriving their efficacy from the dilatation of uncondensible 
gases. The compression of elastic bodies produces heat in amount pre- 
cisely equivalent to the work which has been expended in the compres- 
sion. The reverse operation ought, therefore, to be productive of an 
equal amount of cold. And it is true that it will be so, if the dilatation 
be allowed to take place so soon as the compression is complete, and 
before any portion of the heat which has been produced by this com- 
pression has had time to escape by conduction or radiation. In this case, 
however, the effect of libit., on will be to restore the original tempera- 
ment of the elastic body, and nothing will be gained for purposes of 
refrigeration. To secure any us ful re suit, therefore, by operating on 
this principle, it is necessary that the heat of compression should be got 
rid of before the dilatation is all >wc d to begin. In this case, the result- 
ant temperature will be below that at which the operation ■■••■' >>oed, 
and will be further below in proportion as the compression was greater ; 



394 PAEIS UNIVERSAL EXPOSITION. 

but it will not be true that the elastic body will absorb, in dilating, the 
same amount of heat which it yielded up in the compression. If one hun- 
dred cubic metres of air, at the temperature of 20° C, were to be forcibly 
compressed into one-eighth part of its bulk, its temperature would rise 
four hundred and ten degrees, and the developed heat would amount to 
eleven thousand nine hundred calories. But if by artificial cooling, or 
by abandonment for a sufficient time to itself, this body of condensed air 
should be brought back to its initial temperature, and then allowed to 
dilate to its original bulk, it would fall but one hundred and seventy-one 
degrees, and would lose only four thousand nine hundred and seventy- 
five calories. Thus, more than half the force expended in the compres- 
sion is ineffectual for any useful purpose. The loss is greater in propor- 
tion as the compression is carried further ; but, on the other hand, with- 
out large compression, no considerable effect can be produced, unless by 
employing very large forcing-pumps and very capacious reservoirs, with 
correspondingly increased danger of loss by conduction and radiation. 
The usual mode of employing this system of artificial refrigeration has 
been to permit the escape of the condensed air, after it has returned to 
the normal temperature, into a refrigerating vessel charged with a liquid 
not liable to congeal, in which are immersed the vessels containing the 
substances to be acted upon. The cooling of the condensed air is in 
great measure effected during the progress of the condensation, by inject- 
ing cold water in the form of spray. One great disadvantage of the pro- 
cess, which will be obvious on a moment's thought, is, that the expanding 
air will produce a considerable part of its effect in the reservoir in which 
it was condense], and will carry over only a portion of it to the refrige- 
rator. But the circumstance which will always prevent its successful 
introduction as a form of profitable industry, is the comparatively small 
return which it is capable, under the most favorable circumstances, of 
making for a given expenditure of fuel. The heat produced by compres- 
sion is, of course, only the mechanical equivalent of the force employed 
to compress. Suppose that the whole of this could be made effectual 
for the object in view; inothei words, suppose the apparatus to be capa- 
ble of absorbing just as many calories as are developed in the compressed 
air, and that there was none of that large and inevitable loss which we 
have seen to be the essential condition of applying the machine to any 
useful purpose at all; let us on this supposition make the computation, 
what will be the effect of a single horse power, expressed in kilograms 
of ice produced. A horse-power is equivalent to two hundred an d seventy 
thousand kilogrammetres per hour. A calory is equivalent to four hun- 
dred and twenty-four kilogrammetres. A horse-power may then be rep- 
resented by 636.8 calories, and this number of calories corresponds in 
amount to the heat set free by 6 A3 kilograms of water at 20° 0, in 
becoming ice at zero. It is a steam-engine of the highest class in point 
of economy which furnishes a horse-power of force without an expendi- 



TWINING S AMERICAN ICE APPARATUS. 395 

ture of coal exceeding one and a half kilograms per hour. The product- 
iveness of this process cannot, therefore, much exceed four kilograms of 
ice to the kilogram of fuel, even on the supposition that there is no 
waste, either necessary or accidental.^ But the unavoidable losses arising 
from the necessity of absorbing the heat developed by compression, and 
from the expenditure in part of the effect of dilatation, within the reser- 
voir of condensed air itself, and not in the refrigerator, will reduce the 
actual product from one-half to three-quarters ; so that it would not be 
safe to count on securing more than one kilogram of ice for each kilo- 
gram of coal consumed, even were the air to contribute to the fluid ot 
the refrigerator all the cooling effect of which, when it reaches there, it 
is theoretically capable. There is, however, the additional disadvantage 
to be considered, that the air, being a very bad conductor, exchanges 
temperatures only slowly with other substances which it encounters, and 
that as it bubbles through the fluid into which it is discharged, much 
of its refrigerating x>ower is carried away with it. The production of cold 
by means of the dilatation of compressed air is not likely, therefore, to 
become a profitable industry. 

An apparatus of this kind was, however, patented in England in 1850, 
and continued for a time to operate. About the same time a similar 
apparatus was set up in the city of New Orleans, in regard to the economi- 
cal results of which the proprietors spoke prospectively with great con- 
fidence. But before its capabilities could be folly tested, the building 
which contained it was unfortunately destroyed by fire, and the experi- 
ment is not known to have been renewed in this country. 

TWINING^ AMERICAN ICE MACHINE. 

We return now to consider the refrigerating apparatus of Professor 
Twining, spoken of above. This is the first arrangement ever invented 
for the production of ice with economy and on a commercial scale. The 
possibility of achieving so valuable a result had been demonstrated many 
years before, and this demonstration was also made by one of our own 
countrymen. Jacob Perkins, an American in England, celebrated for 
his inventions, patented in that country an arrangement consisting of a 
vessel immersed in water from which ether is pumped in vapor into 
another vessel, and there recondensed by pressure and by the cold 
of water exterior to the condenser, The restored liquid flows back of 
itself into the exhausted vessel. Around this vessel ice collects, which 
must be broken off or otherwise detached. This apparatus was capable 
of small uses, but was never introduced into practice, so far as is known, 
even for those. 

The invention of Professor Twining was first patented in England on 
the 3d of July, 1850. The United States patent for the same was issued 
November 8, 1853, and afterwards extended to 1871. This patent covers, 
under certain modifications, all the practical machines since operated, 



396 



PARIS UNIVERSAL EXPOSITION. 



whether in the United States or in foreign contries, by the evaporation 
and. restoration of volatile liquids. It explicitly describes four distinct and 
simple modes of combination, by means of which an exhaust vessel, a 
pump, and a condensing vessel, or "restorer,'' may be applied to manufac- 
ture ice in bulk. In all these there is used a freezing cistern, made with 
water chambers open to the air, and which either hold the substances to 
be cooled or the separate water vessels containing water to be frozen. 
Fig. 86. Ihe water chambers are sim- 

ply open spaces conveniently 
enclosed between thin metal 
plates, partitions, pipes, &c, 
which together form chan- 
nels in which a cold liquid or 
vapor is made to circulate in 
contact with the plates of 
the water chambers, and to 
freeze through them. The 
annexed drawing, Fig. 86. 
sufficiently explains Twin- 
ing's patent. 1 The cylinder 
a a a is a pump which ex- 
hausts, or draws in through 
its valves and pipe on the 
side e e' e", and compresses 
or forces out on the side g g' . 
The former may communi- 
cate as at e 1 with the air-tight 
exhaust vessel, or cistern. (7 d 
d. the latter being a box so 
constructed with thin metal 
plates and partitions (or 
equivalent pipes) enclosed 
in it and united to it, alter. 
** nately on one side and its 
opposite, and also at top and 
bottom, as to form th? re-en- 
tering spaces or water cham- 
bers m m m. These also 
create an open winding way. 
ooo, through the box and 
between the plates, such that 
cistern through the pipe p ]). 




Twining's Apparatus for Refrigeration. 

cold fluid drawn or forced into the 



1 As a single drawing is made to illustrate several different modes of operation, superfluous 
connections were necessary. Parts not in action must be left out of view in following the 
modes respectively. 



TWINING'S AMERICAN ICE APPARATUS. 397 

must pass around between and under the water chambers, from end to 
end, and pass out by the pipe e' e. Water vessels, m' m' m', nearly fitting 
these chambers, may be set into them, and the contact of the two made 
complete by an uncongealable liquid (salt water for example) filling 
between the water vessel and the sides of the water chamber. These 
are the only parts necessary to the first and simplest operation for freez- 
ing, which is as follows : A volatile liquid, as ether, snlphuret of carbon, or 
other, fills in part the channel o o o, but leaving room above the liquid 
for its vapor to pass over through o o o to the pump a a a, which draws 
it in. The same pump next forces out the vapor into a coiled condenser, 
or tubular restorer, jjj, surrounded by cold water flowing constantly 
through c c c. This restorer spreads into and discharges in a chamber 
underneath the coil the vapor condensed therein by cold and pressure. 
By the pipe/J'jf', and through p p, connected by a suitable opening and a 
cock, the liquid is conducted back into the cistern. The cold produced by 
vaporization in the spaces o o o, together with the flow of cold vapor 
along the water chambers, freezes through the uncongealable liquid and 
the water vessels. The frozen blocks will become loosened from the 
water vessels by exposure for a short time to the air, or to water of an 
ordinary temperature. The blocks actually made by the freezing appa- 
ratus have been purely transparent, except at and near the middle, and 
in size a foot square by six inches thick. 

A second mode of operating is to provide a separate exhaust vessel, 
B B, communicating by the aid of suitable connecting pipes and cocks 
(as 1, 2, 3, 4) through e" p' p p o o o and e' e with the exhaust of the 
pump, and receiving again the restored liquid at the top of B B along 
jjj and the larger return or circulation pipe C 0. The pump, in action, 
will draw cold vapor from the volatile liquid in B B (through o o o and 
p p' e") in contact with the sides of m m m, and freeze water, or cool 
other substances, in those water chambers. This constitutes, essentially, 
the operation by expansion and restoration of liquid carbonic acid set 
forth by Mr. T. C. S. Lowe, in his patent of April 2, 1867. 

A third mode of employing the above freezing combination was speci- 
fied in another imtent issued to Twining, April 22, 1862. Preserving 
every part of his apparatus, as last mentioned, (the cocks 1 and 3 being 
open, but 2 and 4 closed,) a small circulation pump, b &, is added for the 
purpose of drawing the cold liquid itself out of B B, by the large con- 
duit D D, and forcing it through p p p into and through o o o around 
the water chambers, and then returning it to B B through 0. This is 
the form and operation originally employed at Cleveland, Ohio, in 
February and March, 1855, with an exhaust-punrp of eighteen inches 
stroke and eight and a half inches bore, capable of producing a ton of ice 
in twenty -four hours ; and which did produce, under disadvantages, six 
hundred and sixty-one pounds in eleven hours and ten minutes. It was 
also the publication of these results that first brought the practicability 
of the ice manufacture to public knowledge. 



398 PARIS UNIVERSAL EXPOSITION. 

Still a fourth mode of employing the above-named invention was 
described in Twining's original patent, and it is the mode which was 
taken up and employed in England after the publication of the Cleveland 
results. In this the exhaust vessel B B is supplied with vertical tubes 
closed beneath, or entering a cul-de-sac, allowing the ether to run down 
and its vapor to escape upward. The vaporized liquid thus abstracts 
heat from a contiguous uncongealable liquid that surrounds the pipes, 
and, in its cold state, is drawn out by the pump b &, in place of the cold 
volatile liquid described in the preceding paragraph. The same pump 
also circulates it in open troughs which contain the water vessels. This 
modification having been reserved, although described in Twining's 
patent issued in 1852, was afterward secured to him by another patent 
issued April 15, 1862. 

Finally, a fifth mode of operating — and one of the four first mentioned 
as being described in the original patent — is the following : independ- 
ently of B B and b b and their connections, the exit pipe jjj of the 
restorer is prolonged into d d c7, in a coil Jc Jc cooled by exposure to the 
cold vapor in ddd. The same is further prolonged into a u percola- 
tor " which, to adopt the language in the patent itself, lies along the 
vessel (cistern) in or near one of its upper angles. This has certain 
perforations or perforated branches or channels (see JcJa) girdling every 
exposed side of each water-cJiamber, and made to inject the ether in jets, 
or drops, or films, upon or between its exposed surfaces or coatings. The 
volatile liquid thus spread upon or running down the water-chambers 
freezes through the uncongealable liquid and the water vessels in those 
chambers. 

Having thus presented evidence which must be esteemed conclusive 
that the problem of artificially producing intense cold was first solved 
practically and economically in America, it may be interesting to add, 
in the words of the inventor himself, some brief account of the early 
history of the invention, as given in a statement printed but not pub- 
lished in 1857. He says : 

"The first experiments were mere elementary trials, made as far back 
as the year 1818. By maintaining a vacuum in a small reservoir of ether 
immersed in water, the weight of ice which the evaporation of a given 
quantity of ether would produce was proved. 2sext, by computing the 
power necessary to effect that evaporation, there was found a sufficiently 
promising result to encourage a prosecution of the subject. The experi- 
ments were repeated, till 1850, under different forms and with accordant 
results. It appeared that one pound of ether, by its evaporation, was 
adequate to produce one pound and one-fifth of ice from water of 32° 
F, besides cooling down the ether 28°. 

"The next question arising was whether the ether vapor could be re- 
conclensecl with sufficient rapidity. By numerous experiments it was 
ascertained that only two hundred superficial feet of thin copper pipes 
would form an adequate surface for the manufacture of two thousand 



EXPERIMENTS WITH TWINING's ICE APPARATUS. 399 

pounds of ice in a day of twenty-four hours, even employing water of the 
temperature at the earth's equator. 

u It was next to be ascertained whether the evaporation itself could 
be made sufficiently rapid. By trial it was found that one superficial 
foot evaporated, in a partial vacuum, five and a half pounds of ether per 
hour, even at the low temperature of four degrees above zero. This 
wonderful result proved that the evaporation, even at such a low tem- 
perature, had proceeded three-quarters as fast as that of water in the 
boilers of locomotive engines on railroads. In this, as well as in several 
subsequent particulars upon which the entire practical value of the in- 
vention depends, it was found that nature, so far from opposing the 
theory by difficulties in practice, was far more land than theory, by itself, 
could have ventured to anticipate. 

" Again, it had been supposed, prior to these experiments, that the 
non-conduction of heat by ice would interpose an impracticability in 
respect to the enormous surface necessary to freeze water in bulk. It 
was made to appear, however, that a congelation of one-eighth of an 
inch in thickness could be realized per hour, and that two hundred and 
forty superficial feet would be a sufficient exposure for one ton of ice per 
day of twenty-four hours. It was besides ascertained that the rate of 
freezing was not appreciably obstructed by the thickness of ice already 
formed. 

"The first attempt at a complete freezing construction was made in 
the summer of 1850. The machine had only capacity to freeze a pail-full 
of water at one operation. It embraced the evaporating, the condensing, 
and the freezing parts of the present engine and apparatus. But the 
mode of applying the freezing power was widely different. Six months 
were consumed in trials with this machine, and the most discouraging 
practical difficulties were brought to light. It was not till long after- 
wards that the inventor could discover the proper modes of obviating 
these difficulties. Nevertheless, this first small machine served as a com- 
plete verification of the facts, principles, and numerous small experi- 
ments which had been relied upon ; and it thus became an encourage- 
ment, in the end, to attempt a vastly larger construction. 

"The present engine was in readiness for a first experiment February 
15, 1855. It was calculated to produce two thousand pounds of ice per 
day in ten freezing cisterns of cast iron, each divided into seven water 
chambers. With only two cisterns of the ten, three hundred and seventy- 
one pounds of ice were made in eight hours ; and, in addition, thirteen 
hundred pounds of metal were cooled down below freezing temperature ; 
the aggregate result appearing to demonstrate that the machine, with 
its full complement of cisterns, would be competent to the production of 
two thousand seven hundred pounds per day, instead of the two thousand 
for which it was intended. The freezing, however, was too rapid ; and 
the ice, although of fair quality, was too crystalline, as well as somewhat 
porous. The water employed for condensation was thirty times in quan- 



400 PARIS UNIVERSAL EXPOSITION. 

tity the water frozen ; and "both were taken, at temperatures of 70° to 
80°, from the hot water well of the steam-engine. Tiie cold current of 
the cisterns lowered progressively from freezing temperature down nearly 
to zero ; and here it may he mentioned that, as an experiment of mere 
curiosity, or information, the temperature has at times been made to 
descend even to twenty-six degrees below zero. In the vacuum vessel 
the tension of vapor in the above experiment began with 5.7 inches of 
mercury, and ended with 2.7 inches. In the restorer the tension rarely 
exceeded two pounds above the atmosphere. 

"By a trial, March 2, the product of ice was six hundred and sixty- 
one pounds in eleven hours ten minutes, with only four cisterns. By 
computing the aggregate of effect it was demonstrated that the machine 
could maintain a complement of at least one-third more cisterns than 
had been originally assigned to it. 

"In different trials made during the summer, eight cisterns of the ten 
were put on. The machine will at any time freeze up in these cisterns 
fifty-six cakes of ice, each one foot square and six inches thick, and 
weighing together sixteen hundred and eighty pounds. With ten cis- 
terns a ton could be frozen. This entire effect is produced by a pump 
of only eight inches and a half bore and eighteen inches stroke, work- 
ing ninety double strokes per minute, together with small auxiliary 
pumps for water, ether, &c. In the greatest heats of July the vacuum 
vessel and the conducting pipes become coated with snow, and clear 
icicles hang down wherever water drops upon them. The machine has 
been operated, at different times, for some two years, and no corrosion 
of the metals has been observed, beyond the ordinary action of the atmo- 
sphere. In its operations there is no defect; but there are considerable 
defects of construction. In this last respect it has, as might be expected, 
the imperfections of a first machine — offering the experience by which 
great advantage will be realized in subsequent constructions. 

"The ice produced by the above machine is equally sound with natural 
ice, and, doubtless, equally durable. Probably its specific gravity is even 
greater, on account of the complete expulsion of air during the conge- 
lation, and the consequent absence of air bubbles. It is either glassy 
clear or pearly white, according to the temperature and other circum- 
stances of the freezing. Experiments, instituted for the purpose, show 
that these circumstances are capable of complete regulation." 

ECONOVIY OF PRODUCING- ICE BY TWINING S APPARATUS. 

In regard to the economy of manufacture, the inventor presents the 
following estimates, which, having been made for 1S57. may require some 
modification at the present time : 

"The cost per ton of the ice produced is, for any particular locality, a 
question of mere arithmetic, when the data for calculation arc well set 
tied, viz., the price of fuel and of labor, and the scale of the manufae- 



ECONOMY OF TWINING's ICE APPARATUS. 401 

ture. For a scale of seventy-five to eighty-five tons each twenty-four 
hours, and wherever coal can be procured at ten dollars per ton, and or- 
dinary labor at one dollar and twenty-five cents per day, the cost will be 
about one dollar and a halfjter ton, after the manufacture shall have be- 
come settled into its best condition. At first it may be prudent to count 
upon two dollars to two dollars and twenty-five ceuts. On a scale of say 
ten tons per day, the cost may, at first, range as high as three dollars 
and fifty cents. This inequality of cost is due mainly to the fact that 
the attendance upon a ten ton engine must be nearly the same as upon 
one of eight times the capacity. With respect to capital — meaning 
thereby the entire outlay for the establishment — it will be seen by the 
estimates given in detail below that a seventy-five ton establishment, in 
New Orleans, would require about one hundred and fifty thousand dol- 
lars. Probably a ten ton establishment, under the same circumstances, 
would require twenty-five thousand dollars or thirty thousand dollars. 

Besides its low first cost the manufactured ice will afford several ad- 
vantages of economy, compared with the imported article. First. Ice 
houses, except for a few tons capacity, will be dispensed with, as well 
as the labor of storage and of unpacking. Second. During distribution, or 
transportation, the cakes will lie packed like cut masonry. Third. The 
labor, time, and waste of dividing blocks and weighing will be done 
away with. Fourth. The surplus necessary, in irregular masses, to in- 
sure the delivery of full weight, will be saved. Fifth, and most impor- 
tant of all. The distributing carts will load at the manufactory ; so that 
the article, delivered as just made, may unite the profits both of the pres- 
ent importation and, in a large measure, of the present distribution, 
still underselling the present market. 

If the foregoing statements are well established, it is obviously a set- 
tled fact that the warm climates of our country are soon to be supplied ivith 
artificial ice by means of this invention. How much further this assertion 
might be justly extended is immaterial at present. Evidently where 
the demand is most urgent the supply should first be provided/' 

Professor Twining prepared, in full detail, estimates of the cost of 
erecting in a great city, say New Orleans, a manufacturing establish- 
ment, capable of producing eighty tons of ice per day. The amount of 
capital which would be required for the creation of such an establish- 
ment with its machinery complete, and including the cost of building 
and grounds, he concluded would not exceed one hundred and sixty 
thousand dollars. The daily expense of maintenance, including fuel, 
wages, repairs of machinery and building, oil, ether, and all contingen- 
cies, he computed at one hundred and twenty dollars. If to this we add 
interest at six per cent, on the investment, amounting to twenty-six dollars 
and thirty cents, the total cost of eighty tons would be one hundred and 
forty-six dollars and thirty cents, or one dollar and eighty-three cents 
per ton. It was a large allowance for waste and expense of distribution, 
therefore, when the inventor assumed, for purposes of comparison, the 
26 I A 



402 PARIS UNIVERSAL EXPOSITION. 

total cost to the producer at five dollars or six dollars per ton, in the 
following statement of conclusions: 

" The first cost of ice to the retailer in Xew Orleans at the present 
time — including waste and expense of distribution — is variously stated 
at ten dollars to sixteen dollars per ton. The same, under the new sys- 
tem, would he five dollars to six dollars. Ice, in that city and in most 
other southern cities, commands readily from twenty dollars to forty dol- 
lars. It is quite safe, therefore, to put the profit upon the manufactured 
article ten dollars per ton. Supposing then, at first, eighty per cent., or 
more, of the profits appropriated to reimburse the capital, principal and 
interest, and then, when the establishment lias cost the capitalist nothing. 
the profits thenceforth to be divided equally between the capital inter- 
est and the patent interest, the foregoing data make it obvious that a 
very unusual margin of profits on the original investment is exhibited, 
even though that investment is already repaid." 1 

It cannot be too much regretted that an invention of such merit and 
importance, and of which the soundness and commercial value had been 
so fully demonstrated, both theoretically and experimentally, should, 
through the apathy or timidity of capitalists, have been permitted to lie 
neglected in the country in which it originated, till foreign enterprise 
had seized upon it, and developed it into a great industry. 

x In the American Journal of Science and Arts for I860 will be found two papers by Dr. 
John Gorrie on the heat developed by the compression of air. These papers are in substance 
a resume" of the results obtained by him in a series of experiments conducted on a large 
scale at the instance of some capitalists of New Orleans, who had in view, as he says, 
a commercial object — probably the manufacture of ice. These persons may have been the 
same by whom the enterprise spoken of in the text was set on foot. Dr. Gorrie writes under 
the impression, natural at that date, that the freezing effect of the dilatation will be equiva- 
lent to the heating effect of the compression. He endeavors, by the discussion of the results 
of his experiments, to ascertain the law which governs the relation between pressure and the 
ultimate temperature — a law which Poisson, however, had already established, and which it 
would be somewhat difficult to discover by methods entirely empirical. The experiments of 
Dr. Gorrie have a certain practical interest ; but the progress which has been made within the 
last twenty years in the science of thermotics deprives them of value considered as contribu- 
tions to theory. 



CHAPTEE XIII. 
LIGHT-HOUSE ILLUMINATION. 

Display of objects connected with the construction and operation of light- 
houses—Models of English light-houses— Use of the magneto-electrical ma- 
chine— Wigham's GAS-LIGHT FOR LIGHT-HOUSES— THE GAS-LIGHT COMPARED PHOTO- 
metrically with the light from colza oil lamps— the bailey light house — 
Flashing light at Wicklow Head— Report to the board of trade upon the 
relative advantages of gas and oil for light-house illumination— letter 
to Admiral Shubkick— Electric light— Light as produced by battery— By 
magneto-electric machine— regulators of electric light— the british mag- 
neto-electric machine in the exposition — tlie french machine— economy of 

THE ELECTRIC LIGHT — THE ELECTRIC LIGHT AT La HEVE — FOG PENETRATING POWER 
OF THE ELECTRIC LIGHT COST OF MAINTENANCE AT La HEVE— LaDD'S DYNAMO- 
ELECTRIC machine — Magneto-electric machine of Dr. Werner Siemens — 
Wilde's machine — Experiments and apparatus of Mr. C. W. Siemens and of 
Professor Wheatstone — Advantages of Ladd's machine. 

It is not designed under this head to pass in review the various inter- 
esting objects connected with the construction and operation of light- 
houses which were brought together in the Exposition by the govern- 
ments of England and France. The display made by these two great 
nations was exceedingly comprehensive in its extent and admirable in 
its character, well worthy indeed of the prominent position occupied by 
those nations as maritime powers. France exhibited not only every 
description of optical apparatus for illuminating light-houses, but also 
models and drawings of light-house towers, and even the real towers 
themselves. One of these, a beautiful iron structure, fifty-six metres 
high, (more than one hundred and eighty feet,) crowned with a revolv- 
ing light of the first order, was constructed for the Eoches Douvres, a 
reef off the north coast of Brittany, where it is to be placed after the close 
of the Exposition. Another was presented as an illustration of the form 
of the French harbor light-houses, and was only eight metres in height. 
Both the French and the British governments exhibited electric lights, 
the briDiancy of which, especially of the former, excited great admiration. 
The models of light-houses exhibited by England were particularly inter- 
esting. There were fifteen of these, presenting on a reduced scale not 
only the towers themselves, but also fac-similes of their sites and of the 
surrounding topography. There was also shown a model of the light- 
ship at the Goodwin Sands, one side of which had been left open to 
exhibit the arrangements of the interior. 

The exhibition of light-house apparatus, however, complete and inter- 
esting as it certainly was, presented little that could be called new. The 
most important improvement made in the system of sea-coast lighting in 



404 PARIS UNIVERSAL EXPOSITION. 

recent times has been the introduction of the inagneto-electrical machine 
to supply illuminating power. This innovation was first made by the 
British light-house authorities in 1862, who, after some preliminary ex- 
periments made at the light-house of the South Foreland, established 
the electric light permanently at Dungeness ; and it has been since 
adopted by the French government in the two important light-houses at 
La Heve. 

The importance to the security of navigation, and therefore to the 
interests of commerce and the safety of property and life, of a system of 
coast lights, the most effective which can be obtained by combining all 
the resources of science and practical skill, gives to every proposition for 
the improvement of these lights a claim to a careful consideration. The 
point, therefore, to which, in connection with the exhibition of light- 
house appliances, the present reporter directed his attention with the 
deepest interest was electric illumination practically and economically 
considered in the light of the experience which has been thus far 
acquired in regard to it. The results of the inquiries instituted will be 
found below. In the mean time, it may be observed that, inasmuch 
as notwithstanding the superiority of the electric light, this light can- 
not be established except in localities where certain geographical and 
physical conditions conspire to favor its installation, the desirability of 
improving the illumination of light-houses by other modes is not by any 
means diminished. The following brief account of such an attempted 
improvement now gradually making its way in the British islands, will 
not, therefore, be without interest : 

L_WIGHAM'S GAS LIGHT FOE LIGHT-HOUSES. 

Upon the coast of Ireland, in the vicinity of Dublin harbor, there are 
one or two light-houses which, since 1865, have been illuminated by gas- 
lights instead of oil lamps. They furnish a light superior to that given 
by the largest four- wicked Fresnel oil-burner, by photometric measure- 
ment, as four to one. They are, at the same time, maintained at a cost 
less than had been previously required to light the same light-houses 
with oil, in the proportion of three to four. The plan having been in 
the first instance adopted experimentally, has since so fully established 
itself in the confidence of the light-house authorities of Great Britain and 
Ireland as to have been made permanent in the locality where it was 
first introduced ; and measures have been taken to extend it. to other 
points of the coast of both islands. 

This important improvement had its origin in an effort made by the 
Ballast Board of Dublin to provide increased securities against the 
dangers to which shipping is exposed in approaching their harbor. In 
the following extract from the Irish Times for August 25. 1865. will be 
found some account of the measures taken by the board in the prosecu- 
tion of this effort : 

"The corporation for improving the port of Dublin, best known as the 
Ballast Board, is the authority having charge of the entire light-house 



wigham's gas-light for bailey light-house. 405 

service of Ireland ; and it is not saying too much that there is no corpo- 
rate body in any country which, in the discharge of most important and 
responsible duties, gives greater satisfaction to the public, and more 
efficiently and promptly attends to the matters which come under its 
control, and upon which the safety of our maritime population so much 
depends, than the Dublin Ballast Board. 

"The royal commissioners, in their report upon the condition and 
management of lights, buoys, and beacons, (1861,) bear testimony to the 
efficiency of this board and their care for the public welfare. One of the 
most recent proofs of this has been given in the establishment of a new 
light of very great brilliancy on the Hill of Howth, at the point known 
as the Bailey light-house. As the most easterly point of the bay of 
Dublin, and marking the entrance to our crowded river, it is of immense 
importance that the light in such a position should be of surpassing 
power, and, if possible, possess a capability of penetrating the fogs which 
at certain seasons of the year prevail upon our coast. Having this in 
view, the Ballast Board applied to Mr. John R. Wigham, gas engineer, of 
the firm of Edmund son & Co., of Capel street, a gentleman of great ex- 
perience in such matters, to make certain experiments with the view of 
discovering a light of greater illuminating power than any hitherto used 
in the light-houses of Ireland, and the result has been the invention, 
by Mr. Wigham, of what may be termed an oxygenated gas-light of great 
intensity. The great peculiarity of Mr. Wigharu's light is its whiteness. 
To this is due its power of penetrating fogs to a much greater extent 
than any other lights used for light-house purposes, excepting, indeed, 
the lime light and the electric light. The danger of explosion connected 
with the use of the former, and the expense and complicated machinery 
required for the production of the latter, render both of them unsuitable 
for universal application. But Mr. Wigham's system is exceedingly 
simple, and, requiring no skilled labor to direct its operations, is suitable 
for any position, no matter how remote or isolated. We have had an 
opportunity of making photometric observations respecting it, and find 
the light produced by Mr. Wigham's iuvention to be nearly three times 
greater than that afforded by the large four-wick oil lamps heretofore in 
use in the dioptric lens apparatus of the first order power of light-houses, 
while it would appear that the cost is considerably smaller in proportion. 

" Having satisfied themselves by repeated experiments of the superi- 
ority of the new light, the gentlemen comprising the Ballast Board, 
with their chief adviser, Captain Roberts, B. N., one of the highest 
authorities upon such subjects in this country, determined to adopt it 
at the Howth Bailey light-house, and consequently our seafaring friends 
and those residing on the coast of Kingstown, Dalkey, &c, have had for 
some time back the opportunity of observing its brilliancy, which strik- 
ingly contrasts with the old light exhibited from that point. All the 
parts of the apparatus necessary for producing Mr. Wigham's new 



406 PARIS UNIVERSAL EXPOSITION. 

patent light are manufactured in Dublin, and thus, through the instru- 
mentality of the Ballast Board, a new source of manufacturing industry 
is likely to be opened up. 

" The deputy master of the Trinity House Corporation of London, 
(the board having the control of English light-houses,) accompanied by 
several of the elder brethren, having heard of the new light, came across 
in their steamer (the Argus) specially to inspect it. They expressed 
themselves much pleased with its appearance, and the deputy master 
spent some time in testing its superiority by means of Mr. Wigham's 
photometric apparatus. It must, therefore, be gratifying to every one 
interested in the prosperity of this country and its advancement in man- 
ufactures, that this light of Dublin invention is likely to find its way 
into English and Scotch light-houses, as well as Irish, and that foreign 
countries also will avail themselves of a discovery eminently calculated 
to lessen the danger of the seas and promote the prosperity of maritime 
commerce." 

The following additional notice of the new light is from the Dublin 
Daily Express of the 28th August, 1865 : 

" The great prevalence of fogs on large tracts of our ship-studded shores 
is, as is well known, the cause of much of that lamentable loss of life and 
property which takes place at sea. Heretofore fog-bells, placed on the 
dangerous parts of our coasts, have been in use, but only with partial 
success, to supplement the ordinary beacons — the light-houses. The 
light diffused by the latter, though amply sufficient in clear weather, 
will not penetrate a sea-fog to such a distance as will secure, or even 
materially assist in securing, the safety of the mariner when exposed to 
such a danger. Even landsmen require not to be told how a light which 
can be seen in clear weather from a great distance, becomes invisible a 
few yards off when surrounded by a fog. The lights at present in use in 
the light-houses on the English and Irish coasts are generally powerful 
enough to be visible in clear weather as far as any light can be seen, 
namely, until they disappear beneath the horizon ; but in hazy or foggy 
weather they are almost useless. It is, therefore, obvious that the 
invention of a light which shall be intense enough to overcome, to a great 
extent, the resistance to its diffusion which foggy weather presents. 
would be one of great importance. Toward the discovery of such a 
light the Dublin Ballast Board have recently been directing their atten- 
tion, and very considerable success has attended this movement on their 
part. After partially succeeding in their attempts to improve the ordi- 
nary oil light hitherto used in the light-houses under their control, and, 
indeed, in all light-houses, they, feeling satisfied that some still more 
powerful and equally available description of light might be procured, 
applied to Mr. John E. Wigham, of the firm of Messrs. Edmundson £ 
Co., of this city, and requested him to use his knowledge and practical 
experience as a gas engineer in solving the important problem. That 



wigham's gas-light at bailey light-house. 407 

gentleman, believing that light obtained from gas was more capable of 
improvement than that produced from oil, commenced operations by 
experiments having for their object the invention of gas of a better and 
purer quality than that in general use. He not only succeeded in pro- 
ducing gas of a quality much superior to any hitherto made, but he 
obtained that result by the simplest means — the gas being produced 
from oil by a safe and simple process. The light thus produced, and 
which is denominated oxygenated oil gas, is of intense brilliancy. On 
its being shown to us in Messrs. Edmundson's establishment it appeared 
to cast over the room, which had been previously darkened, a light of a 
similar, though, of course, not equally intense, whiteness and purity as 
is produced by electricity or the magnesium wire ; and we could easily 
understand how powerful it must prove when transmitted by the care- 
fully-adapted apparatus fitted up in all light-houses. 

"As is well known, all gas, though giving out a pure white light as 
it emerges from the burner, yet becomes dark and smoky at the extrem- 
ity of the flame. This defect Mr. Wigham has succeeded in obviating 
by a very simple yet ingenious method, so that the entire flame becomes 
equally white and pure. Another recommendation which it possesses 
is, that notwithstanding its superior power — giving about three times 
as much light as the old light-house oil-burner — it can be produced at 
even less cost, and it does not require the presence of skilled labor to 
superintend or manage it. 

"On the 16th instant this new light was substituted for the old oil 
light formerly in use at Howth Bailey light-house, and with complete 
success, its great brilliancy being the subject of general remark on the 
part of all who have witnessed it. The Ballast Board sent a deputation 
of their number to test the comparative power of the new and old lights, 
and the result was most satisfactory. The deputy master and other 
members of the Trinity House Corporation, London, have since also 
inspected it, and expressed their unqualified approval of it ; and we may 
expect shortly to hear that it has been adopted by them for the purpose 
of illuminating the English light-houses which are under their charge." 

Interested by the statements which had reached him concerning this 
light during the summer of 1867, the present writer, at the close of the 
Exposition in November of the same year, visited Dublin for the purpose 
of becoming personally familiar with the facts in regard to it. He was 
received with great courtesy by the gentlemen of the Ballast Board, by 
whom every facility was allowed him for visiting the light-houses into 
which the new system had been introduced, and for examining all the 
details of the constructions, and testing the performance of the apparatus. 
Mr. John R. Wigham, their gas engineer, very politely placed himself at 
the writer's service, and personally accompanied him, first to the light- 
house on the Hill of Howth, where the new light had been in use about 
two years ; and afterwards to Wicklow Head, about twenty miles from 
Dublin, at which all the constructions and preparations for introducing 



408 PARIS UNIVERSAL EXPOSITION. 

it had just been completed. The Wicklow light is a flashing light, and it 
serves to bring out some points of the superiority of the new system of 
illumination more strikingly than the other, which is fixed. 

Before visiting the light-houses an opportunity was offered the writer 
to compare, photometrically, the intensity of the gas-light with that of 
the flame of a first-class four- wicked Fresnel oil-lamp, burning the best 
kind of colza oil. The comparison was made in the photometric gallery 
of Messrs. J. Edmundson & Co., of Capel street, Dublin, the house of 
which Mr. Wigham is a partner. The gas-burner, which was a fac- 
simile of those used in the light-houses, consisted of a cluster of thirty 
jets arranged in concentric circles, and giving a very powerful compound 
flame. The result more than sustained the statements contained in the 
extracts from the Dublin journals above given, as the photometer showed 
a superiority on the part of the gas-light as four to one. This was 
understood to be owing to the improvements which have been made 
upon the apparatus since its first introduction. 

THE BAILEY LIGHT-HOUSE. 

The Bailey light-house on the Hill of Howth was next visited, and an 
attentive examination was made of the arrangements for manufacturing 
and purifying the gas, as well as of the fixtures for exhibiting the light 
in the lantern. The stand for the lamp is not removed ; but the lamp 
itself is promptly detachable, being united with the stand by a simple 
joint made secure against leakage and hydrostatic pressure by means of 
mercury. When the lamp is in place, the oil is supplied from a reservoir 
of suitable height within the lantern. The supply is cut off when the 
lamp is to be removed, by means of a stop-cock. On raising the lamp a 
certain amount of oil escapes from it, which is caught in a receiver 
attached to the stand, from which it may be drawn off and returned to 
the reservoir. When the gas-burner is introduced, it takes the exact 
place previously occupied by the lamp, being adapted to its own sup- 
port by means of a mercury joint similar to that above mentioned in 
speaking of the lamp. As the support is necessarily a little eccentric in 
the lantern, the leading tube below the burner is so curved as to bring 
the cluster of gas-flames precisely into the required position. Above 
the burner is placed a large glass chimney, which serves to create a 
draught by which smoke is effectually prevented, and the flame is made 
intensely bright and clear. 

An opportunity was afforded to the writer to see the change effected 
from gas to oil. The burner was removed and the lamp substituted in 
its place and lighted, all within about one minute. 

The gas which was used in the earlier experiments was manufactured 
from oil, but the material now employed is cannel shale. This is distilled 
in retorts precisely like those of our ordinary city gas works. Two retorts 
were used at Howth Bailey, but in the construction of the new works 
three have been introduced as affording greater security against possible 
accidents. 



USE OF GAS FOR LIGHT-HOUSE ILLUMINATION. 409 

FLASHING LIGHT AT WICKLOW HEAD. 

A visit was made on a subsequent occasion to the flashing light at 
Wicklow Head, about twenty miles distant from the former by land. 
Here the great advantage of gas for intermittent flames was made very 
strikingly evident. By means of a simple clock-work movement and a 
mercurial valve, the gas is instantaneously cut off at the proper moment, 
and is afterward as instantaneously rekindled by means of small main- 
taining flames, such as are to some extent in use in this country for 
domestic lights. The mechanism previously used to display and con- 
ceal the oil light was greatly more elaborate, and was liable, on the least 
disturbance of adjustment, to work with a clatter, which, being re-en- 
forced by the vibration of the entire column of air in the tower, was 
almost deafening. 

RELATIVE COST OF GAS AND OIL. 

At the time of the writer's visit to Wicklow Head, in 1867, the gas- 
light had only just been introduced. With the caution with which light- 
house authorities proverbially proceed, the results of the single experi- 
ment at Howth had been watched for nearly or quite two years before 
the introduction of the system elsewhere had been permitted. Early in 
1867 a report on the subject was called for by the Board of Trade in 
London, which was furnished by E. F. Roberts, esq., inspector of lights, 
of Dublin, as follows : 

a The experiments commenced in the year 1865 with gas made from 
oil, and subsequently with gas made from shale, the latter being more 
economical, and showing an equal amount of light. 

"On comparing the gas with a four- wick lamp, the photometer showed 
the gas-light to be four times greater in intensity and quantity than the 
oil light of the four- wick burner, such as is used in a first class dioptric 
apparatus. 

11 Several comparisons were made by observing the effect of each from 
the Princess Alexandra steamer at night, in the following manner, viz : 

a The four- wick oil lamp at Howth Bailey was lighted for half an hour 
to enable the flame to reach its proper height; it was then suddenly 
extinguished, and the gas was exhibited in the space of a few seconds, 
when the superiority of the gas was very manifest. These experiments 
were made on many occasions. 

"Again, the steamer was taken to a position equidistant from Howth 
Bailey and Wicklow Head, the night being perfectly clear, both apparatus 
of the same order, and both, when burning oil, showing the same bril- 
liancy; but, on substituting gas at the former station, its superiority was 
again very evident. 

"On the 27th of December, 1866, an accident happened to the gas, 
owing to a defect in the coupling of the gas-pipe, when oil had to be 
used, which was done in about a minute. But such an accident is not 
likely to occur again. 



410 



PARIS UNIVERSAL EXPOSITION. 



" I would still recommend the gas to be continued at Howth Bailey, 
and also adopted at Wicklow Head for the intended intermittent light, 
but in no case would I propose it without having oil in readiness, as a 
stand-by in case of accident. 

"Annexed is a statement of the annual cost of maintenance of gas- 
light for the year 1866, exclusive of the interest on the first cost for 
fitting up the gas apparatus, (which amounted to the sum of two hun- 
dred and forty pounds,) also a statement of the expenditure for main- 
taining the oil light at Wicklow Head during the same period, the lamps 
at this station being exactly similar to those at Howth Bailey. 



"OIL. 

" Annual statement of the quantity of 
oil and other material expended in 
maintaining the oil light at Wick- 
low Head light-house station, witfi 
the cost of same between the 1st Jan- 
uary and 31st December, 1866. 

£ s. d. 
780 gals, of oil at Is. 9JcZ. 186 17 6 

Lamp wicks 5 6 

Cylinders 4 40 

Carriage of oil, &c 4 8 

Burners, and repairs of 

burners 3 10 



Total 204 5 6 



"PATENT GrAS. 

u Annual statement of the quantity 
of fuel, materials, &c, expended in 
manufacturing gas at the Howth 
Bailey light-house station, with the 
cost of the same, between the 1st 
January and 31st December, 1866. 

£ s. d. 

Coal, 38 tons, at 24s 



Shale, 14 tons, at 67s. 2d. 
Lime, 96 hhds, at Is. Id. 
Labor, 365 days, at 2s. 



45 12 

47 4 

6 8 

36 10 

Cylinders, 35, at Is 1 15 

Oil, (during accident to 

gas,) 5 gals, at 4s. 1M. 14 7 
Wear and tear, fixing 

spare retort 6 00 

Wear and tear, fixing 

new gas burner 2 



Total 146 9 11 



" Total number cubic feet of gas produced 120.439 

" Total number cubic feet of gas consumed 118,137 ? ' 

In consequence of this report the following correspondence took place 
between the Board of Trade and the inspector, which is introduced as 
covering the principal points of practical interest in this system of light- 
house illuminations: 



THE SECRETARY OF THE BOARD OR TRADE TO CAPTAIN ROBERTS. R. N. 

"Board of Trade, Whitehall March 30. 1S67. 
"Sir: With reference to the report upon the shale gas-light at Howth 
Bailey light-house, forwarded in answer to a query, I am directed by the 



USE OF GAS FOR LIGHT-HOUSE ILLUMINATION. 4 1 1 

Board of Trade to request that they maybe furnished with the following 
additional information : 

" 1st. The cost of the entire apparatus, machinery, and buildings re- 
quired for the system of gas illumination. 

" 2d. The space occupied by the apparatus, &c, i. e., the size of the 
buildings for the apparatus, including stowage of coal, shale, lime, &c, 
over and above the space necessary for the common system, and 
whether such space could be obtained at a rock station, where the tower 
alone is available. 

"3d. Whether additional labor is required, as it has been charged at 
Howth Bailey. 

"4th. How is the crocus burner used, with reference to the common 
dioptric apparatus '? Is it placed in the focus of the lenses, or is it inde- 
pendent of them ? 

"5 th. When the accident happened to the gas, how long did it take to 
repair; and supposing it had occurred where no aid was at hand beyond 
the keepers, could the accident have been remedied ? 

"6th. Is the retort liable to sudden injury, and what would be the 
result % n 

REPLY OF CAPTAIN ROBERTS. 

Ballast Office, Dublin, April 24, 1867. 

"Sir: With reference to the Board of Trade's letter of the 30th ulti- 
mo, requesting that they may be furnished with additional information 
respecting the system of gas illumination for light-houses, 

"I beg to submit to the board the following answers, viz.: 

"1st. The cost for the entire apparatus, machinery, and buildings, 
requisite for this system of illumination, depends to some extent on the 
position of the light-house to which it is to be adapted ; but taking, for 
instance, Wicklow Head, the following is an approximation of what the 
cost is likely to be, viz. : 

" A complete gas apparatus, with crocus burner and buildings, including 
coal-store, is estimated to cost as follows : 

[Here follow specification and details of cost, omitted.] 

"2d. The space required for a gas apparatus would be about sixty feet 
by twenty feet, including storage for coal. I am of opinion it would 
not be suitable to apply gas to any rock station, where such space out- 
side the tower could not be had, as it would not do to make gas in the 
tower. 

"3d. I consider one additional laborer is necessary for making the gas. 

"4th. The crocus lamp is placed in the focus of a lens, and is remova- 
ble and replaceable by the ordinary oil lamp in three or four minutes. 
No alteration of the lenses is required in the case of using gas. 

" 5th. The accident referred to in my report was simply a leakage. The 
light-keepers found it as they were going to light up, just before sunset, 
and although they could easily in a few minutes have repaired it with a 



412 PARIS UNIVERSAL EXPOSITION. 

little white lead, yet they thought it better to light the oil lamp and 
repair the leakage by soldering, which they did; and at 9.30 p. in. they 
took away the oil lamp and lighted the gas, the change occupying one 
minute and a half. 

"A similar leakage cannot occur again, as the brass cap which was in 
contact with the quicksilver of the coupling, and which had become cor- 
roded by the action of the quicksilver, has been replaced by iron, which 
will not be so acted on by the quicksilver. 

" Gtli. The average duration of a retort is one year ,• they sometimes 
last much longer. They seldom crack suddenly, but this does sometimes 
happen. Such a crack can generally be easily staunched with a little 
tar and fine coal dust, and a retort so treated often lasts a long time. 
When a retort at any time, either from ordinary wear or sudden crack- 
ing, becomes too leaky for use, recourse is had to another, which can be 
used until it in its turn requires to be replaced. By the arrangement 
proposed for Wicklow Head, the three retort beds are to be so constructed 
that a new retort can be placed in any of them without stoppage to 
the gas manufacture, so that there will be little chance of failure in the 
light from breakage of retorts; and as they are almost the only perish- 
able part of the apparatus, the continuance of the light is pretty cer- 
tain, and in addition there is the i stand-by' of the oil lamp.'" 

As the result of these inquiries, an order was shortly after issued for 
the introduction of the new system of gas-lighting at Wicklow Head. 

In addition to these evidences of the superiority of the new light, it 
may be stated that numerous written testimonials in its favor have been 
given by the most experienced navigators frequenting the port of Dublin, 
including the officers of the royal navy commanding the royal mail 
steamers entering that port. From all that he had thus seen and heard 
upon the subject, and in view of the magnitude of the improvement and 
of the simplicity and cheapness of the means by which it had been 
effected, the writer became strongly impressed with the desirability of 
introducing a system possessing so great advantages into some of the 
more important light-houses upon the American coast. Owing to the 
necessity of manufacturing the gas upon the spot where it is to be used, 
the system is not adapted to light-houses upon isolated rocks, or to minor 
lights remote from the sources of supply of the necessary material ; but 
in such localities as Fire Island, Sandy Hook, and many other points in 
the approaches to our great seaport towns, its introduction would be 
unattended with difficulties of any kind, and it could not fail to promote 
in a high degree the security of navigation. Impressed with these views. 
the writer availed himself of the earliest opportunities which presented 
after his return to this country, in the winter of 1807, to bring the sub- 
ject informally to the attention of members of the Light-house Board of 
the United States. At the expressed desire of some of these gentlemen. 
he went so far as to obtain exact estimates of the probable cost of con- 
structing and maintaining the necessary works in connection with a 
light-house in a selected locality, from Messrs. J. Edmundson & Co.. of 



USE OF GAS FOR LIGHT-HOUSE ILLUMINATION. 413 

Dublin, the originators of the system, and from a competent gas engineer 
of New York. These estimates, accompanied by drawings, were for- 
warded to the chairman of the Light-house Board at Washington, with 
the following explanatory letter, dated Columbia College, New York, 
April 10, 1868, and addressed to Admiral W. B. Shubrick, chairman of 
the Light-house Board : 

LETTER TO ADMIRAL SHUBRICK. 

"I have the honor to forward to you, herewith, estimates of the cost 
of constructing and erecting gas works suitable for supplying a first-class 
light-house, proposed to be illuminated by Wigham's patent crocus gas- 
lamp, as actually employed at the Howth Bailey and Wicklow Head 
light-houses, in Ireland. 

"There are two estimates entirely independent of each other; one by 
J. Edmundson & Co., Dublin, the house to which Mr. Wighani belongs, 
and the other by Mr. H. J. Davidson, a civil engineer of this city, who 
has had experience in the erection of gas works, and whose drawings 
are taken from works actually existing in this city. Mr. Davidson's 
estimates and drawings were furnished before I had received those of 
Edmundson & Co. Both reach substantially the same result. Each 
includes something which the other does not. 

"Edmundson & Co. propose to deliver in New York all the apparatus 
necessary for the purpose proposed, upon the plan of the works at Wick- 
low Head, (the most recently constructed of the Irish works,) and to put 
in place all the pipes and fixtures necessary for illumination, including 
alteration of the present oil-lamp so that it may be used interchangeably 
with the gas-burner in case of need ; but do not undertake the erection 
of buildings or the setting of retorts. 

"This estimate amounts to one thousand and fifty-five pounds; or, with 
gold at one dollar and forty cents, say to seven thousand four hundred 
dollars. 

"Mr. Davidson proposes to furnish everything in Edmundson & Co.'s 
offer, with a second purifier, a washer and a meter besides, which are 
not required at Wicklow ; but he does not undertake the erection of the 
apparatus and fixtures, nor will he provide the burner. 

"His estimate is six thousand dollars, with a gas-holder of one thou- 
sand cubic feet capacity. But as a larger gas-holder — say two thousand 
five hundred cubic feet — will be necessary, his total will amount to 
seven thousand five hundred dollars, or about the same as that of 
Edmundson & Co. 

"From Mr. Davidson's estimate may be deducted the value of the 
parts not necessary, which will reduce the total below seven thousand 
dollars. 

"Neither estimate includes the cost of buildings, nor the work of set- 
ting the retorts, or of constructing the tank of masonry required for the 
gas-holder. Mr. Davidson states to me that all these expenses may be 



414 PARIS UNIVERSAL EXPOSITION. 

kept within four thousand dollars, or perhaps three thousand five hun- 
dred dollars, but that the retort house ought to have an iron roof, (this 
is not the case at Howth Bailey or Wicklow, but I think it ought to be,) 
and such a roof will cost one thousand dollars. 

"Both propose to deliver the works in New York. Transportation 
could not cost to any point which the board would probably select for 
the experiment — for instance, Sandy Hook — a very large sum. 

"I put down, therefore, as quite outside estimates of all the items 
involved in the original outlay : 

Buildings 84,000 

Iron roof retort house 1,000 

Works (in Xew York) 7,500 

Transportation 500 

Total 13,000 

which is probably one or two thousand dollars in excess. 

"As to the expense of maintenance, the crocus burner carries thirty 
bats- wing jets, each burning, it may be assumed, five cubic feet per hour, 
or the whole, one hundred and fifty cubic feet per hour, and one thousand 
eight hundred cubic feet on an average per day, through the year. The 
total consumption will therefore be six hundred and fifty-seven thousand 
cubic feet per annum, which will require seventy-three tons of coal to 
produce it. 

73 tons of coal, at $9 per ton 8657 

800 bushels of lime, at 10 cents SO 

Total cost of production of gas per annum 737 

"The actual cost at Howth Bailey for illuminating material during the 
year 18G6 was £100 Is. lid. ; or, at the present price of gold, about seven 
hundred dollars. 

"At Wicklow Head, during the same year, (the gas-lamp not having 
been yet introduced,) the cost of the oil consumed, as delivered at the 
light-house, was £191 5s. 6^7., or about one thousand three hundred and 
forty dollars. The lard oil used in the American light-houses may, how- 
ever, be cheaper. 

" If gas is introduced into any of our light-houses, an additional attend- 
ant will be necessary ; his services will, perhaps, cost five hundred dollars 
per year. We may put, then, 

Cost of illuminating material 8737 

Cost of additional labor 500 

Total 1,237 

showing a slight economical difference in favor of gas : the incidental 
expenses being about the same for both modes of lightiug. 

"As to the quality of the light, I can testify, from my personal obser- 
vation, to the great superiority of the gas-light. During a stay of sev- 



GAS FOR LIGHT-HOUSES THE ELECTRIC LIGHT. 415 

eral days at Monkstown, near Kingstown, Dublin harbor, last November, 
the Howth Bailey light was every night visible at a distanee of six miles, 
and was greatly more brilliant than a first-class oil light with a cata- 
dioptric lantern of the same description situated at half the distance." 

It will be noticed that, in these estimates, the values given are in 
excess, especially for the maintenance of the light, of what they are 
likely to prove to be. Coal delivered at Sandy Hook will probably cost 
more nearly six than nine dollars per ton. The additional labor required 
will probably be obtainable for two or three hundred dollars per annum, 
instead of five hundred. If the same description of coal is used as at 
Howth Bailey, a much less weight will be necessary than is here 
assumed, though at a price in like proportion perhaps advanced ; but 
the gas will be richer and the volume consumed very greatly less. 

Supposing, however, that there should be nothing whatever gained ; 
or even supposing that the expense of the gas-light should be sensibly 
greater than that of the lamp-light at present used, the advantage secured 
by the change would be out of all proportion to the increased cost, since 
the intensity of the light would be increased four-fold, and the range of 
its visibility in moments of danger would be correspondingly extended. 
If a single ship of the multitudes which founder in the approaches to the 
harbor of New York should be saved from destruction in consequence of 
the adoption of this superior light, the value of this one vessel with its 
cargo alone would be sufficient to pay the increased expense consequent 
upon the adoption of the improvement for an entire century. The pro- 
ject is still before the Light-house Board. It is to be hoped that that 
body may deem it at length to be worthy of a trial. 

II.— ELECTRIC LIGHT. 

The intense light produced by the current of a powerful galvanic bat- 
tery passing between two carbon points, early suggested the possibility 
of employing electricity for purposes of illumination. This could only at 
the time seem a remote possibility, for the want of permanence and 
uniformity of force in the currents generated by the only batteries then 
known, restricted within narrow limits the duration of the phenomenon 
and the steadiness of its brilliancy. When, about thirty years ago, sus- 
taining batteries had been created by Daniell, Grove, and others, the 
problem became more feasible, and excited a new interest. In the 
mean time, however, two great discoveries had been made. In 1819, the 
influence of the electric current upon the magnetic needle, first detected 
by Oersted, laid the foundation of that important branch of electrical 
science to which, among other great benefits, the world owes the electric 
telegraph, and which is known as electro-magnetism ; and in 1830, the 
production of a spark from a circuit of copper wire, suddenly interrupted 
in x^resence of a magnet, a result reached by Faraday in the prosecution 
of his ingenious experimental researches upon electricity, was the ele- 
mentary fact out of which has since grown the converse branch called 



416 PARIS UNIVERSAL EXPOSITION. 

magneto-electricity. The discovery of Faraday was speedily prolific of 
important consequences. It was found that magneto-electric machines 
might be constructed which should furnish, not merely sparks, but pow- 
erful currents. For many of the purposes for which electricity had been 
employed it was found entirely practicable to substitute instead of the bat- 
tery — the maintenance of which, when great power is required, is attended 
with inconvenience and other disagreeable concomitants — an apparatus 
of a much higher degree of simplicity, and demanding only, in order to 
produce the same effect, the expenditure of a certain amount of mechani- 
cal force. Magneto -electricity has accordingly in recent years, to a cer- 
tain extent, superseded the battery current for many practical purposes, 
and especially for the uses of the galvanoplastic arts. 

The magneto-electrical machine is peculiarly adapted to the purpose 
of illumination. As its parts are all unchangeable, or undergo only the 
changes incident to wear and tear, the force of the current which it pro- 
duces will depend only on the amount of mechanical force which is con- 
sumed in driving it. And as this can be maintained sensibly constant, 
the same constancy will characterize the current. Still, however, the 
problem of producing a steady light by means of electricity is not alto- 
gether easy of solution. Though the current may be one which in a 
perfectly uniform conductor would be constant, it is a condition essential 
to the production of the light that the circuit should be broken. The 
light is produced between two carbon points introduced into the circuit 
at the point of rupture. These are usually made of the very hard incrust- 
ations which form spontaneously in the retorts of gas manufactories ; 
and the substance is on that account called gas-carbon. The electric 
generator — magneto-electric machine or battery, as the case may be — 
being in action, these carbon points are brought momentarily into contact, 
and then separated from each other. While contact continues, no light 
appears. In the instant of separation the light bursts into brilliancy. 
The distance of separation which is practicable will depend on the inten- 
sity of the current. If this distance is made too great, the current will 
cease to pass. A certain degree of intensity is necessary on the other hand, 
in order that there may be any separation at all without a cessation of the 
current ; or in other words, that the production of light may be possible. 
With a given perfectly sustained force of current, and a given pair of 
carbon points, it would seem, then, that after having found the degree 
of separation of the points which produces the most brilliant illuminating 
effect, we should only have to fix them there to make this effect perma- 
nent. And this would be true but for the fact that the points gradually 
waste and thus increase the distance separating them. If, therefore, 
they should be fixed in their places, as just suggested, the current would 
finally fail to pass, and the light would become extinct. 

When the experiment is performed in the lecture-room for purposes of 
demonstration, the experimenter can compensate the gradual waste ot 
the carbons by advancing one or the other of them with the hand. This 



AUTOMATIC EEGULATOES OF ELECTRIC LIGHT. 417 

is even practicable, though not quite convenient, when the light is 
employed for optical purposes, as in the magic-lantern and miscroscope, 
since its variations are not generally very rapid. But, for a permanent 
light, unless there can be provided an automatic and certain compensa- 
tion for this waste of the points, the electric light, notwithstanding its 
beauty and brilliancy, cannot be made available. 

Happily the properties of the electric current itself suggest the means 
of providing such a compensation. When this current passes through a 
wire in the form of a helix enveloping a rod of soft iron, it converts the 
rod into a magnet. It is not necessary that the helix should touch the 
rod ; the effect follows if it only surrounds it. Moreover, in these cir- 
cumstances, if an attempt is made to withdraw the rod from the helix, 
there will be felt very distinctly a resistance arising from the attraction 
of the current in the helix for the rod, an attraction which is only satis- 
fied when the middle point of the length of the rod coincides with that 
of the helix. The force of this attraction varies with the strength of the 
current. An effort which would suffice only to remove the rod a slight 
distance from the position of equilibrium when the battery current is, 
high, would produce a much larger displacement when this current is. 
greatly reduced. 

In this fact we have the principle upon which the automatic regulators 
of electric light, of which quite a number have been produced by differ- 
ent inventors, must necessarily all be founded. Suppose one of the car- 
bon points to be fixed and the other to be connected with a bar of iron 
which partially enters a coil of wire ; through this coil the same current 
may be made to pass which produces the light. The attraction of the 
coil will draw backward the bar, and with it the carbon. In order to. 
prevent too large a movement, this attraction may be counteracted by a 
spring of such force that the carbon remains stationary at the point most 
favorable at the moment to the production of the light. As the carbon 
points waste, the distance between them will increase and the current 
will be enfeebled. The elastic force of the spring will then prevail over 
the attraction of the coil, and the points will approach each other. And 
as the wasting of the carbons and the approaching of the points are both 
gradual, the light will be subject to no abrupt change of intensity. It 
is obvious, however, that a contrivance constructed in this simple form 
could be serviceable only within certain rather narrow limits ; for, in 
order that the spring may prevail it is necessary that the magnetic force 
should grow gradually less; that is to say, that the actual distance 
between the points should after all increase, and the light correspond- 
ingly diminish. An automatic regulator of electrical light requires, 
therefore, for its satisfactory performance, the introduction of other 
mechanical expedients, which it is not necessary here to describe. 

It is a condition of the production of the electric light that it cannot 
be produced in larger or smaller quantity at pleasure. It cannot be pro- 
duced at all except by a current which has power to pass through a sen- 
27 I A 



418 PARIS UNIVERSAL EXPOSITION. 

sible interval separating the two poles of the battery, or, as they are 
called, the electrodes. And a current of this degree of power, when it 
"becomes luminous, becomes intensely so. The electric light is therefore 
unsuitable for the ordinary uses of domestic life, but for purposes of 
public illumination, and especially for sea-coast lights, it seems to 
be admirably adapted. It has been introduced by the governments of 
both Great Britain and France in one or two of their first-class light- 
houses; by the former at Dungeness, and by the latter at La Heve, 
near Havre. The British light was established in 1862 ; the first French 
light, a year or two later. In both cases the electricity is generated by 
powerful magneto-electric machines driven by steam-engines. It was 
stated in the earlier reports that a force of one and a quarter horse-power 
was required to drive the British machine, and one and a half horse- 
power to drive the French. In practice, the French have employed a 
force greater than this, equal to two and a half horse-power for each 
machine. 

Both these governments have exhibited their lights in the Exposition, 
and the French machine has been visible to the public for some hours 
daily. The British has been less freely open to inspection, and on the 
only occasion on which access to it has been obtained, it was enveloped 
in a covering of canvas, which made a detailed examination impossible. 
A description of this machine, however, or at least of one quite similar 
exposed in London, in 1862, furnishes all the essential particulars in 
regard to its construction. 1 The machine embraces eighty-eight bobbins, 
or coils of copper- wire, wound round as many hollow cores of soft iron, 
each containing ninety feet of wire ]^o. 9. The wire is wound in double, 
the whole being equivalent to one wire of forty-five feet in length and two- 
tenths of an inch in diameter. The iron cores are three and a half inches 
long, one and a half inch in diameter externally, and one inch inter- 
nally. They are arranged at equal distances from each other in the cir- 
cumference of a large wheel five feet in diameter, their axes being parallel 

iTbe information which, at the time of writing this article, (September, 1^67,) was 
wanting-, has been since furnished in a published report of Captain M. C. Close, a member 
of the Trinity House Light-house Board, and one of the British commissioners to the Exposi- 
tion. It appears that the electro-magnetic machine exhibited in Paris by the British govern- 
ment was constructed upon a model somewhat differing from that of the Dungeness machine 
described above. Since the differences, however, are not differences of principle or even of 
form, but only of the number of parts and of their arrangement, it has not been thought 
worth while to disturb the statements of the text, but to note the necessary corrections in the 
present form. 

In the machine which was exhibited at Paris the total number of magnetic bobbins is 
ninety-six, and these are arranged in six rings or wheels, and not in two as at Dungeness. 
There are, therefore, seven rings of permanent horseshoe magnets, instead of three. The 
bobbins of the successive rings are set, as described above, in such a manner that one-half 
the number shall be undergoing change of polarity, while the other half are in the middle of 
the spaces between the poles of the permanent magnets, and commutators of course have to 
be used. It is stated by Captain Close that experiments with this machine show that the 
number of changes of polarity per minute which gives the most intense illumination is - : x 
thousand four hundred. 



MAGNETO-ELECTRIC MACHINES FOR ELECTRIC LIGHT. 419 

to the axis of the wheel ; and in two parallel rings, forty-four coils in 
each ring. The axes of one set or ring of coils are placed so as to cor- 
respond to the middle of the distance between those of the other ring. 
Sixty-six very powerful steel horseshoe magnets are firmly fixed in 
three rings parallel to each other, twenty-two in each ring, their poles 
all in the planes of their several rings, and distant from each other by a 
space equal to that which separates the centres of the bobbins. The 
magnets of the several rings are similarly situated upon the circumfer- 
ence, their poles being alternate ; but the poles of those in the extreme 
rings face contrary poles in the central ring. Each magnet in the two 
external rings is composed of four separate plates, or simple magnets, 
combined, and each of those of the central ring of six simple magnets. 
The weight of each simple magnet is six pounds. 

As the wheel turns, the cores with their bobbins pass between the 
successive poles of the fixed magnets; and owing to the equality of the 
spaces between the poles and the cores, all the bobbins of one ring pass 
these poles simultaneously; but owing to the dissimilarity of position of 
the two series of bobbins in their respective rings, it happens that while 
those of one set are passing the poles, those of the other are half-way 
between the poles. While the motion continues, alternate currents of 
opposite character are generated in each series of bobbins. The change 
of polarity and of corresponding electric flow occurs in the moment of the 
polar passage. Thus when the current in one set of bobbins is in the 
middle of its flow, that in the other undergoes a sudden reversal. By 
the arrangements known to electricians under the name of commutators, 
all the successively opposite currents are turned into the same direction 
in the circuit which conveys the electricity to the electric lamp. In this 
way the fluctuations which occur in the intensity of the current gener- 
ated by one of the sets of bobbins are made to compensate those of the 
other, and the resultant intensity is nearly or quite constant. 

As the twenty-two magnets of each ring present forty-four poles, there 
are forty-four changes of direction in each set of bobbins at every revolu- 
tion, or eighty-eight changes in both. The velocity of revolution is at 
the rate of one hundred and ten turns per minute. The total number of 
changes of polarity in the same time is therefore nearly ten thousand. 
The intensity of the light produced depends on the rapidity of revolution. 
When the movement is slow the current is feeble, as when the machine 
is at rest there is no current at all. But though the intensity increases 
with the velocity, a limit is reached beyond which a further acceleration 
will tend to diminish rather than to increase it further, because the 
magnetization of the soft iron cores is not instantaneous, but requires a 
certain time, and too great a velocity of revolution induces a reversal oi 
the current before the cores are completely magnetized. The most 
advantageous velocity can only be ascertained experimentally. 

The French machine in some respects differs from the English. There 
are four rings of bobbins, instead of two, but only sixteen in each ring 



420 PARIS UNIVERSAL EXPOSITION. 

or six cry-four in all. They revolve between five sets of steel magnets, eight 
in each set. All the bobbins are similarly situated in the circumferences 
of their respective rings, so that they all pass the poles of the magnets 
simultaneously. The diameter of the wheel, measured from centre to 
centre of the opposite bobbins, is one metre. The cores of the bobbins 
are hollow iron cylinders, one decimetre (nearly four inches) in length, 
and five centimetres, or about two inches, in external diameter. Their 
internal diameter is three and a half centimetres. Eight wires, one 
millimetre in diameter and sixteen metres long, are wound round each 
bobbin, and are united at their corresponding ends, being equal to a single 
wire of fifty-three feet long and eleven-hundredths of an inch in diameter. 
The magnets of the outside rings are composed of three simple magnets, 
weighing each four kilograms, or nearly nine pounds. Those of the 
intermediate rings have twice as many of the same size. The number 
of revolutions of the wheel is sometimes carried as high as four hundred 
per minute, giving over six thousand alternate currents in the same 
time. No commutator is used. It is an interesting fact that the produc- 
tion of light by a magneto-electrical machine is independent of the 
direction of the current, and unaffected by the changes in its direction, 
no matter how rapidly they may follow each other. The light is undoubt- 
edly produced in successive flashes, but the minuteness of the interval 
between them prevents their being distinguished, so that the light is 
sensibly constant. When these machines are employed, however, for 
the purpose of producing chemical decompositions, it is obvious that 
the alternation of the current would neutralize the effect, unless a com- 
mutator were introduced. 

In the English machine the commutator could not be dispensed with, 
for though, in its absence,* the two currents would conspire in direction 
during a part of the interval between the pole changes, they would 
counteract each other during the remainder. It may even be questioned 
whether* to a certain extent, they do not produce this effect, notwith- 
standing, the presence of the commutator. If, in the general circuit in 
which they are united, there were absolutely no resistance, each would 
indeed contribute its full force to the current. But if, in this circuit, the 
resistance were to become infinite, or, in other words, if the general 
circuit were entirely broken and the electrodes insulated, each of the 
two currents would be turned back upon the coils of the other, and the 
feebler would be reversed. In the case of their equality they would 
balance each other and there would be no flow. The resistance presented 
by rupture between the carbon points is not infinite, but it is considerable, 
and it must, therefore, produce some effort on the part of each current 
to return through the wires of the other. The French arrangement 
seems consequently to be more judicious than the English. It is attended 
with the additional advantage that the waste of the two carbon points 
is equal; a circumstance contributing to simplicity in the construction 
of the regulators. 



INTENSITY OF THE ELECTRIC LIGHT. 421 

In regard to the intensity of the light produced by these machines, as 
compared with that derived from other sources, Mr. Becquerel, in an 
article on the electrical apparatus exhibited in the Exposition of 1862, 
gives some interesting statements derived from the results of experiments 
made at Paris with a magneto-electric machine similar in construction 
to that above described, but having six sets of bobbins instead of four, 
or ninety-six in all. The permanent magnets were similar, and each was 
capable of lifting three times its own weight. The machine was driven 
by an engine of two horse-power, and the light produced, determined by 
suitable photometric measurements, was divided by two, in order to reduce 
it to the amount corresponding to a single horse-power. This amount 
was found, when the electrodes employed were of selected gas carbon, 
to be equal to a mean value of seven hundred stearine candles. Its 
greatest brilliancy was from one thousand to one thousand one hundred, 
and its least from four hundred and eighty to five hundred and twenty. 
With carbon of greater purity, specially prepared for the purpose, the 
mean light was from eight hundred to eight hundred and eighty, and 
the maximum nearly one thousand three hundred. 

Mr. Becquerel proceeds to compare the light thus obtained, in point of 
economy, with that produced in equal quantity by the galvanic battery, 
by coal gas, by coal oil, by oil of colza, by tallow, stearine, and wax. In 
these estimates he assumes the price of gas to be thirty-hundredths of a 
franc per cubic metre, or seventeen cents the one hundred cubic feet ; 
oil of colza, one dollar and twenty-eight cents per gallon ; tallow, in the 
form of candles, sixteen cents; stearine, thirty-six cents; and wax fifty- 
two cents per pound. The cost of the electric light he assumes to be only 
that of the combustible required to run the engine. From these data he 
deduces the following values : 

A light equal to that of seven hundred stearine candles will cost per 
hour — 

1. Produced by the machine 2 to 4 cents. 

2. Produced by the galvanic battery 38 to 94 cents. 

3. Produced by coal gas 62 cents. 

4. Produced by kerosene 73 cents. 

5. Produced by pure oil of colza $1 14. 

6. Produced by tallow candles $2 37. 

7. Produced by stearine $5. 

8. Produced by wax $6 10. 

In point of cheapness, therefore, there would seem to be no comparison 
between the electric light and that produced by even the least costly 
of the materials ordinarily employed for purposes of illumination. 
Actual experiment, however, in the use of these machines in French 
light-houses, has shown that these figures require important modification. 
A report made in 1866, to the minister of public works, by Mr. Eeynaud, 
inspector general of roads, bridges, light-houses, and buoys, upon the 
electric light established at La Heve in 1864, furnishes some valuable 



422 PARIS UNIVERSAL EXPOSITION. 

information in regard to this matter. The lights at La Heve are of the 
first class and two in number, situated about one hundred yards apart. 
The lanterns are at one hundred and twenty-one metres (nearly four 
hundred feet) above the level of the highest tides. One of these lights 
only was replaced by electricity in 1864, the other continuing to be 
maintained, as before, by means of an oil lamp. The presence of the 
two descriptions of light, side by side, furnished thus the most advan- 
tageous opportunities to compare them not only as to the cost of 
maintenance, but also in regard to their regularity, the range of 
their visibility and their power of penetrating fogs. In regard to this 
latter property it is an important fact that the fog-penetrating power 
of a light is not necessarily proportioned to its brilliancy, whether 
as apparent to the eye or as photometrically determined. Fogs and 
smokes absorb powerfully the more refrangible rays of the spectrum, 
while allowing the red and yellow — that is to say, the most highly 
luminous — rays to pass with comparative facility. It is this which 
tints the clouds of the morning and evening horizon so forcibly with 
orange and rosy hues, since the horizontal rays of the sun then traverse, 
for a great distance, the lower strata of the atmosphere, which are more 
or less charged with mists. The light which is produced at excessively 
high temperatures is dazzling iu its brilliancy, and possesses the white- 
ness of the solar light. This is due to the presence in it, in their full 
proportion, of the most refrangible and most easdy absorbable rays. 
The electric light is of this character. In the light produced by the 
combustion of oils, on the other hand, these easily absorbable rays are 
but feebly represented, while the red and yellow are produced in abund- 
ance. Accordingly, in a time of fog, an electric light may show but a 
moderate superiority over a light produced by an oil lamp which, by 
photometric nieasureineut. it at the same time exceeds in the proportion 
of eight or ten to one. In clear weather, on the other hand, it will have 
a much greater range of visibility. 

The electric light established in 1861 at La Heve was provided with 
two magneto-electric machines like that above described, having each 
four disks of sixteen bobbins, and having each its independent driving 
engine. There were also provided two systems of Fresnel lenses, one 
above the other, having each two regulators for the carbon electrodes. 
This duplication of all the parts of the apparatus was especially intended 
as a guarantee against any interruption of the light by unforseen acci- 
dent ; inasmuch as in case one regulator failed, another could be substi- 
tuted, and in case one machine ceased to perform, the other could be put 
immediately in motion. But an incidental and great advantage resulted 
also from this provision, which consisted in the power to double the 
intensity of the light whenever the atmosphere was unusually thick. 

The power of the beam thrown by the magneto-electric machines 
originally established at La Heve, as concentrated by the cata dioptric 
system of Fresnel, was found to be equivalent to that of three thousand 



INTENSITY OF THE ELECTRIC LIGHT. 



423 



five hundred Carcel burners. The light which it replaced, and that of 
the companion light which for a time remained, had only the force of 
six hundred and thirty Oarcel burners. After the new light had been 
put into operation, the point of principal interest first attended to was 
to ascertain, by comparative observations, the mean relative visibility or 
range of visibility of the two lights. Observations were accordingly 
made three times every night by the keepers of the three lights at 
Honrleur, distant fifteen kilometres, or eight and one-tenth miles; at 
Fatouville, distant twenty-one and a half kilometres, or eleven and six- 
tenths miles ; and at Ver, distant forty-six and five-tenths kilometres, or 
twenty -five and one -tenth miles. 

The following table presents the results : 



Place of observation. 



Distance. 


















S 

o 


a> 


















a 


d 




M 


15 


8.1 


21.5 


11.6 


46.5 


25.1 




Honfieur . 
Fatouville 
Ver 



1.04 
1.02 
1.24 



This table does not furnish a very fair test of the relative value of the 
lights. During the greater number of the nights of observation when 
both lights were seen, a much feebler light than either would probably 
have been equally visible, especially from the nearer points. During 
many of those in which neither was seen, it is probable that a much 
more powerful one than either would have been unobserved also. The 
table shows, nevertheless 5 that while the electric light is superior to the 
other, it is not so much superior as might have been anticipated. It 
shows, further, that its superiority is apparently more marked as the 
distance is greater ; a fact, however, which is associated with the important 
additional fact that both lights are less frequently seen at great distances, 
or, in other words, are seen at such distances more frequently in clear 
weather, when the rays of high refrangibility are least absorbed. In 
foggy weather, on the other hand, though the electric light was seen 
twice or more in the hundred times oftener than the oil light, yet during 
those same times both the machines were in operation, and the power of 
the electric light was carried up from three thousand five hundred to 
seven thousand carcel-burner force, while the oil light remained constant 
at six hundred and thirty. An advantage, nevertheless, which the 
electric light very distinctly possessed over the other, was in its creating 
a kind of glow in the fog, by which mariners were enabled to recognize 
the position of the cape even when both lights were invisible. 



424 PARIS UNIVERSAL EXPOSITION. 

Aii irregularity appears in the table, by which the superiority of the 
electric light would seem to be more marked at Honfleur, the nearer 
station, than at Fatouville, 1 more distant. This is explained by the 
statement that the light of the oil lamp is somewhat obscured in the 
direction of Honfleur by the framework of the lantern. 

An evidence perhaps more conclusive of the relative value of the 
lights than that which the table affords, is found in the testimony of 
navigators, who with one voice affirm that they always see the electric 
light before the other. 

Experiments have been made with the view of ascertaining with some 
approach to accuracy the relative fog-penetrating power of the two 
descriptions of light produced by electricity and by ordinary combus- 
tion, when the photometric intensities are equal ; and also the excess of 
intensity which must be given to the former light, in order that its 
power in this respect may be equal to that of a lamp fed by oil. In 
these experiments it was attempted to imitate as nearly as possible the 
absorbent effect of fogs, by interposing glasses of different colors, red, 
orange, yellow, &c, before each of the lights successively. The conclu- 
sion which these experiments seem to justify is, that whenever an elec- 
tric light exceeds in intensity a light produced by a lainp two and a half 
times, it will penetrate at least as well as the latter the fogs most unfa- 
vorable to the transmission of the rays. And, as a fact, in whatever 
state of the weather, the electric light at La Heve has always had the 
largest range of visibility. 

It is not to be set down as an objection to the use of the electric light 
that it requires to have this excess of intensity over the lights actually 
in general use, in order to be equally serviceable ; because one of the 
conditions of the production of this light is that it shall be intense. 
And there is no difficulty in securing not only the required increase of 
intensity, but even a much greater one, with a much less actual expense. 
Thus, at La Heve, the ordinary intensity of the electric light is nearly 
six times as great as that of the oil light, and when both machines are 
in operation it is about eleven times as great. 

The apparatus required for the production of the electric light is very 
much more complicated than that which is necessary to maintain that of 
the compound lamp in common use in light-houses. The possibilities of 
derangement are correspondingly multiplied. Accident may happen to 
the steam-engine, the magneto-electric machine may fail in some of its 
parts, or the regulator of the carbons — a delicate and somewhat compli- 
cated piece of mechanism — may cease to perform its functions regularly. 
It is on this account that the French government, in introducing the sys- 
tem into the light-house at La Heve, were careful to double every part of 
the machinery and apparatus, even to the costly optical combinations. 
An experience of fifteen months, however, demonstrated that the liability 
to interruption by accident was not great. During this period the num- 
ber of accidents was ten. Five of these occurred with the engine, and 



ECONOMY OF THE ELECTEIC LIGHT. 425 

caused the extinction of the light for periods varying from three to 
fifteen minutes. They were traced to the inattention of one of the 
machinists ; and in an interval of eight months after his discharge, 
there occurred but one more, which interrupted the movement only 
three minutes. Two accidents occurred to the magneto-electrical ma- 
chines. In the first, in consequence of the fracture of a plate, there 
was a stoppage of ten minutes 5 in the second, owing to the derange- 
ment of a bobbin, there was, for a minute or two, a fluctuation of the 
light. These accidents suggested effectual measures for preventing the 
recurrence of similar misfortunes. The other accidents were owing to 
derangements of the regulators, and did not produce extinction. 

The result of this experiment was so satisfactory to the French gov- 
ernment, both as to the practicability of employing the new mode of 
illumination and as to its superior value, that it was resolved to extend 
the system to the second of the light-houses at La Heve. An order to 
this effect was issued by the minister in May, 1865, and the new appa- 
ratus was brought first into use on the second of November of the same 
year. 

The apparatus for the service of both these light-houses is now installed 
in the same building, half-way between the two towers. It embraces 
four magneto-electrical machines, each having six disks instead of four, 
with sixteen bobbins in a disk. Two engines of five horse-power each 
are employed to run these. Ordinarily one engine only is in operation, 
driving a single machine for each tower. In heavy weather both 
engines are active, and each tower receives the combined currents of 
two machines. Both the light-houses have double catadioptric systems, 
one superposed above the other as in the arrangement originally intro- 
duced. The illuminating power of each of the new machines, as opti- 
cally condensed, is equal to that of five thousand carcel lamps. By the 
combination of two at once, in time of fog, this great intensity can be 
doubled. Experience has shown that such a duplication will be neces- 
sary about four hundred hours in the year. No interruption has occurred 
since the installation of the new machines. 

In regard to the question of economy several considerations have to 
be taken into the account, which were overlooked by Mr. Becquerel. In 
the first place, the prime cost of building will be considerably increased. 
A suitable apartment will be necessary for the engine, and a separate 
one for the magneto-electric machines. Then the personnel of the service 
will require an increase of at least two men. Moreover, the necessary 
supply of water for the engine will in many, and probably in most cases, 
present a problem of which any solution must be expensive. Headlands 
are chosen by preference for light-houses, where there are no natural 
springs, and where, on account of the height, it is difficult economically 
to raise water by pumps. The alternative presents itself to construct 
cisterns for the collection of rain-water. The cost of these will vary in dif- 
ferent localities. At La Heve they have been constructed of sufficient 



426 PAEIS UNIVERSAL EXPOSITION. 

capacity to contain one hundred and seventy-five cubic metres, (nearly 
fifty thousand gallons,) at an expense of forty-six thousand francs — nine 
thousand dollars. 

In regard to the maintenance of the light itself, in addition to the cost 
of fuel, which has amounted to nearly one thousand dollars per annum, 
there are to be considered the items of carbon electrodes, amounting to 
three hundred and fifty dollars 5 oil, hemp, cotton, &c, one hundred and 
eighty dollars 5 and repairs and maintenance of the engine and machines, 
four hundred and fifty dollars, overlooked by Mr. Becquerel, and in all 
forming a sum nearly or quite equal to the expense of fuel; besides the 
wages of two additional employes. The entire annual expense of the two 
lights, since both were furnished with the electric apparatus, has been 
seventeen thousand francs, or three thousand four hundred dollars, 
while it amounted to only fifteen thousand one hundred and sixty francs, 
or three thousand dollars, while they were lighted with oil. Taking into 
account, however, the superior intensity of the electric light, the expense 
per unit of light is as seven to one in favor of the electric light. The 
relative economy would be somewhat less, but still very nearly in the 
same proportion, if but a single light were to be provided for at the same 
station. 

In regard to the practicability of extending the system of electric 
illumination to coast lights generally, the French inspector general is of 
opinion that, in the actual state of things, it can hardly be accomplished. 
The system is not economically applicable to minor lights, which are the 
class most numerous, while the magnitude of the constructions which 
it requires, and the quantity of coal which it consumes, are obstacles to 
its introduction in isolated positions, where it is important to reduce as 
much as possible both the size of the structures and the quantity of 
transportation. 

Eecent discoveries in electrical science give rise to the anticipation 
that the bulk and cost of magneto-electric machines may in future be 
materially reduced, and that possibly there may be also some reduction 
in the driving force necessary to produce a given intensity of light. 
One of the most remarkable of the objects presented in the present Expo- 
sition is the machine exposed by Mr. Ladd, of London, under the name 
of a dynamo-electric engine. This machine, of which a representation is 
herewith given, Fig. 87 consists essentially of a pair of soft iron plates of 
about twelve inches by twenty-four, and half an inch thick, wrapped with 
insulated wire about one-tenth of an inch in diameter to the depth of 
four layers. These plates are placed horizontally, one over the other, 
and have at each of their extremities a revolving armature. These arm- 
atures are of the form originally proposed by Mr. Werner Siemens, of 
Berlin, in 1857, being cylinders of soft iron deeply grooved in the direc- 
tion of their length, and wound in the groove with insulated copper wire. 

The armatures revolve in hollow cylinders of equal length, and only 
sufficiently larger to permit them to turn freely. These hollow cylinders 



LADD'S DYNAMO-ELECTRIC MACHINE. 



427 



are formed of two thick bars of soft iron separated by an equally thick 
plate of brass all firmly united and then bored longitudinally. These hol- 
low cylinders are interposed between the extremities of the broad plates 

Fig. 87. 








££-£LJL9.Jta . 



Plan. 




^A^^^^^^^m 



Ladd's Dynamo-electric Machine— elevation. 

wound with wire as above described, serving thus to keep them asunder, 
and the whole are firmly bolted together. The wires of one of the arm- 
atures are connected with a commutator, designed to give a common 
direction to the currents of electricity which may be generated in them ; 
and the extremities of the wire which wraps the plates are connected 
with tangents resting upon this commutator. Supposing then the plates 
to be magnets, the combination described forms a magneto-electric 
machine, and in the rotation of the armature, electric currents will be 



428 PAEIS UNIVERSAL EXPOSITION. 

excited in its enveloping wire. The peculiarity of the arrangement is, 
that the currents thus developed will pass by the commutator into the 
wire which wraps the plates, and if the rotation he in the proper direc- 
tion, will tend to reinforce their magnetism. If, however, the plates are 
not originally magnetic, at least in some degree, the rotation will produce 
no electrical effect. But supposing them to be originally unmagnetic, 
it will suffice to touch the extremity of one or both of them with a steel 
magnet to impart to them at least a trace of magnetism, and then, if 
the armature be rapidly revolved, a current will be generated which 
though at first feeble will quickly become very intense. For the mag- 
netism of the plates is exalted by the circulation of the current in their 
enveloping wire, and this heightened magnetism in turn excites the cur- 
rent to increased intensity. The succession of mutual reactions here 
described, goes on until the rapidity of rotation is too great to allow 
the armature, to be folly magnetized in each of its successively opposite 
polar conditions. 

The other armature has been thus far supposed to be at rest; but 
if now the extremities of the enveloping wire of that armature be con- 
nected with the conductors of an electric lamp, and if this armature 
be also put into rapid rotation, there will be produced a light of most 
intense brilliancy. Or if, instead of the lamp, we employ a platinum wire 
to complete the circuit, this wire will be instantly ignited to incan- 
descence, though of several feet in length and a twentieth of an inch in 
diameter. The power of this small machine is stated by the Abbe 
Moigno in his journal, Les Mondes, (ATay 22, of this year,) as equivalent 
to that of twenty-five to thirty elements of Bunsen. 

This invention of Mr. Ladd is so recent that the machine exhibited in 
the Exposition is almost the first of its land which has been constructed. 
The form and proportions most favorable to the effect remain, therefore, 
yet to be studied. But the surprising energy of the currents developed 
by an apparatus of the very moderate dimensions of that exhibited, 
justify the anticipation that the provision of electric light for light- 
houses will exact, hereafter, much simpler mechanical arrangements than 
it has done heretofore. Steel magnets, in great numbers and of great 
power, will no longer be required at all. If, in describing the mode of 
exciting Mr. Ladd's apparatus to activity, we have supposed for a mo- 
ment the intervention of a steel magnet, this was for the sake of sim- 
I>licity of explanation. Xo such expedient is necessary. Place the 
instrument with its polar extremities north and south, and the induc- 
tion of the earth's magnetism suffices. In the beginning it was supposed 
that it would be at least necessary to introduce into the circuit a feeble 
galvanic battery, but experiment has proved otherwise. Indeed, after 
the machine has once been operated, it will not even be necessary to 
call in the aid of terrestrial induction. Traces of magnetism will hang 
round even soft iron for a long period after it has been once magnet- 
ically excited, and these traces will suffice to start the series of reactions 



WILDE'S MAGNETO-ELECTRIC MACHINE. 



429 



by which the power of the machine is developed, whenever the arma- 
ture is put into motion. 

The idea of turning back upon an electro-magnet, for the sake of aug- 
menting its power, the current generated by itself in the envelope of an 
armature revolving before its poles, is not original with Mr. Ladd. It 
is the second armature, introduced for the purpose of generating a cur- 
rent capable of being directly utilized, which constitutes his invention. 
The history of the successive steps of progress by which this construc- 
tion has been at last suggested, is not without interest. 



Fig. 88. 



Fig. 89. 




Fig. 90. 



Fig. 91, 




Wilde's Magneto-electric Machine 

In the year 1857, Dr. Werner Siemens, of Berlin, whose name has 
been already mentioned above, constructed a magneto-electrical machine, 



430 PARIS UNIVERSAL EXPOSITION. 

in which an elongated cylindrical armature, wound with insulated wire 
in the direction of its length, was made to revolve between the poles of 
a number of parallel steel horseshoe magnets. In the spring of 1866, 
Mr. W. Wilde, of Manchester, England, conceived the idea of turning 
the currents developed by one of the machines of Siemens upon the 
insulated wire envelope of a larger electro-magnet; these currents being, 
of course, brought into a common direction by means of a commutator. 
He anticipated an increase of magnetic energy, and the result justified 
his anticipations. The electro-magnet became powerfully excited. By 
rotating, next, the armature of the electro-magnet, he was able to excite 
to a still higher degree a second and larger electro-magnet, and in like 
manner a third, and so on in indefinite series. 

Mr. Wilde thereupon proceeded to construct an instrument of deter- 
minate proportions and of great power, consisting of a combination 
of a Siemens magneto-electric machine of large dimeusions with a single 
electro-magnetic machine greatly larger, and constructed to be used also 
as a magneto-electric generator of electricity. His machine in the form at 
present constructed by him, is represented in the accompanying figures, 
Figs. 88-91, and has the following dimensions : 

The permanent steel magnets are sixteen in number and fifteen inches in 
length. They weigh three pounds each, and are capable of sustaining 
each a weight of twenty pounds. The armature belonging to this part of 
the apparatus is sixteen or seventeen inches long and about two and a half 
inches in diameter. It is wound with fifty feet of insulated copper wire, 
one- tenth of an inch in dia niter. By means of a pulley at its extremity 
it is driven with a velocity of twenty-five hundred turns in a minute, and 
undergoes accordingly five thousand changes of polarity in the same time. 
The induced currents generated in its envelope by this rotation are 
turned into'a common direction by means of a commutator, and sent into 
the wires of a great electro-magnet which forms the base on which the 
smaller machine rests. 

This electro-magnet is formed of two soft iron plates, three feet long 
by more than two feet wide, and one inch thich. Each of these plates is 
wound with seven strands, each fifteen hundred feet long, of Xo. 10 wire. 
The total weight of the wire, exclusive of that of the iron plates, is half a 
ton. The plates weigh together about a quarter of a ton. These plates 
are placed parallel to each other, and are kept separate at one of their 
extremities by a bundle of iron plates, more than a foot thick interposed, 
through which and the great plates there pass five strong bolts, an inch 
in diameter, binding the whole firmly together. At the opposite end is the 
armature, a cylinder seven inches in diameter deeply grooved in the direc- 
tion of its length, and wound with one hundred and fifty feet of iusulated 
wire of nearly a quarter of an inch in diameter. More recently Mr. Wilde 
has substituted iusulated copper ribbon instead of wire for this envelope. 
The armature turns in a hollow cylinder formed of two masses of iron 
separated by a mass of brass five inches thick, and bored out to a diam- 



wilde's magneto-electric machine. 431 

eter exceeding that of the armature by one-tenth of an inch. This hol- 
low cylinder, bolted to the great plates at their extremity opposite to the 
fastening above described, forms virtually the poles of the great electro- 
inagu et. The armature is driven at the rate of seventeen hun dred revolu- 
tions per minute. The current engendered in its envelope may be employed 
for the production of light or for any other purpose for which electricity 
is needed. Its power is truly enormous. Whether any photometric 
determination of the intensity of the light which it produces has been 
made or not, has not been ascertained, but it maintains in full incan- 
descence carbons of the extraordinary size of nearly an inch square. To 
drive it when in full action, a three horse-power engine is necessary. 

The Alliance Magneto-electric Company of France, by whom the 
machines were furnished for the light-houses of La Heve, have purchased 
from Mr. Wilde the right to use his machines, and their power, as com- 
pared with the machines hitherto in use, will probably soon be known. 
In respect to weight, Mr. Wilde's machine is hardly an advance upon 
the old ones. Its total weight amounts to a ton and a half. The rotating 
parts are, however, much less ponderous, being merely cylinders of small 
diameter instead of huge and heavy wheels. Less of the driving force 
of the engine will therefore be expended against the passive resistances 
of friction and the air, and a greater part will probably be transformed 
directly into light. 

When the power possessed by a magneto-electrical machine to excite 
magnetism in another similar machine had thus been demonstrated by 
Mr. Wilde, it was not a long step to take to the conclusion that the same 
machine would manifest a corresponding power to exalt the magnetism 
of its own magnets, provided the currents were turned back upon itself. 
This idea occurred to Mr. C. W. Siemens, of London, and about the same 
time to the distinguished physicist, Professor Wheatstone. Both these 
gentlemen have, within the present year, [1867,] communicated to the 
Eoyal in Society of London the results of successful experiments made 
by them in demonstration of its truth. 

The forms of apparatus employed by Messrs. Siemens and Wheatstone 
furnished but imperfect means of deriving electric effects from the cur- 
rents generated. They obtained none at all except by introducing into the 
circuit by which the magnetism was maintained, the objects upon which 
they desired the effects to be produced, and then the result was com- 
paratively unsatisfactory ; or by splitting the current into two, and di- 
verting the greater portion of it away from the magnet. Mr. Ladd's 
introduction of the second armature has removed the disadvantages 
attendant on either of these arrangements. The magnets receive the ben- 
efit of the full currents of their armatures, and the external work which 
the electricity is required to perform has the benefit of a current entirely 
equal. At first thought, indeed, Mr. Ladd's arrangement might appear 
to be only a different mode of dividing the power ; in other words, it might 
seem that as the magnets through the second armature perform a certain 



432 PARIS UNIVERSAL EXPOSITION. 

external work, this must be at the expense of the magnetism which they 
receive from the first armature. There is a fallacy in this reasoning. The 
electric force which the second armature is instrumental in developing, is 
the mechanical force imparted by the driving power transformed. It is 
the influence of the magnet which effects the transformation, but this is 
not exercised at the expense of its magnetism. A magneto-electrical 
machine in which the same influence is exercised by permanent steel 
magnets, is a demonstration of this. Mr. Ladd's machine has therefore 
reduced the production of electricity by mechanical force to the sim- 
plest, the most effectual, and, apparently, the most economical form. 



CHAPTER XIV. 
PRINTING AND THE GRAPHIC ARTS. 

Printing presses— Color printing presses— Rotary presses— Numbering 
presses— Dressing tvpe— Printing without ink— Gilding and bronzing of 
characters— Stereotyping— Sweet's stereotype matrix machine— Flamms 
typographic compositor— composing and distributing machines— mitchell's 
machine— Graphic methods and processes — Panicography— Pyrostereotypy— 
Lithography— Metallography — Continuous printing from engraving on 
metal —Lithographic printing rollers— Engraving— Polypantograph — En- 
graving BY ELECTRICITY — DULOS'S METHOD OF ENGRAVING — HeLIOGRAPHY— PHO- 

to-lithography — Photograph enamel. 

I.— PRINTING PRESSES. 

The display of printing presses in the Exposition was very fine, 
especially in the French section. Among these, however, were few, if 
any, presenting interesting novelties. That which came nearest to pos- 
sessing this character was one exhibited by Mr. A. -Y. Gaveaux, of Paris. 
This was a reciprocating cylinder press, in which the cylinder, as 
well as the form, receives a horizontal motion. The two movements 
being in opposite directions, there results an economy of space, which 
may, perhaps, be a compensation for the greater complication. This 
press has not yet been fairly tested, and to what extent the construction 
may be advantageous remains to be proved. 

For imparting the necessary reciprocating motion to the horizontal 
table or bed which receives the forms in cylinder presses, three different 
descriptions of mechanism are employed by different constructors, or in 
different presses of the same constructors, all of which are possibly 
already known in this country. One of these, which was illustrated in 
the presses of Messrs. Klein, Forst, and Bohn, of Johannisberg, Prussia, 
and Messrs. Kdnig & Bauer, of Oberzell, Bavaria, is what is known as 
the movement of De La Hire, or the epicycloidai wheel. This consists, 
in fact, of two wheels, one of them fixed in a horizontal position to the 
framework of the press and provided with an interior gearing, in which 
there runs a satellite wheel of half the diameter carried by a crank turn- 
ing on an axis concentric with the fixed wheel, while in its turn it im- 
parts a regular reciprocating rectilinear motion to the table, by means of 
a pin at a point in its circumference. The motion imparted in this man- 
ner is remarkably smooth and satisfactory. 

Another description of movement, introduced some years since by Mr. 
P. Alauzet, of Paris, has an analogy to the contrivance employed by 
28 I A 




i'f 



434 PARIS UNIVERSAL EXPOSITION. 

Mr. Ericsson for regulating the motion of the pistons in his hot-air en- 
gine, as described earlier in this report. Considering that the neatness 
of an impression is promoted by applying the pressure deliberately, and 
that time is economized by the quick return of the form after the impres- 
sion has been made, Mr. Alauzet imparts the desired motion to the 
movable table of the press by connecting it with the free extremity of a 
swinging lever, pivoted at the other extremity and operated in the man- 
ner represented in the figure annexed. In 
this figure, CE is the lever, and G its cen- 
tre of vibration. EK indicates the mode 
of connection with the movable table. A 
gear-wheel, A, has a pin P, which passes 
through a slot in the lever, and gives it a 
vibrating motion from the position C E to 
the position C E ; . The wheel itself receives 
its motion of revolution from the pinion B. 
_-3 While the point P is describing the lower 
E ' ^part of its revolution, the motion of the 
Alauzet's Printing Press. lever, as is obvious from an inspection of 
the figure, is comparatively slow. This is the period of impression, the 
motion being in the direction from E toward E'. During the remainder 
of the revolution, P describes the upper portion of its course, which is 
materially shorter than the other ; and this is the period of return from 
E' to E. 

Another form of mechanism for producing the necessary reciprocating 
motion in presses constructed on this principle, consists in a pair of 
horizontal racks with their teeth vertical and facing each other, which 
are alternately acted upon by a pinion less in diameter than the space 
between the two. These racks being connected with the movable table 
of the press, give to it a motion which is direct or reversed according as 
one or the other is in gear with the pinion. In order to permit this alter- 
nation to take place, the arbor of the pinion has in it a universal joint ; 
but it is a consequence of this construction that the rotation of this 
arbor, which in the fixed portion is uniform, is subject, in the part which 
carries the pinion, to a periodical irregularity, causing slight differences 
in velocity of movement between the type and the cylinder, which are 
unfavorable to clearness of impression. Notwithstanding this disad- 
vantage, the mechanism here described has long been in use in the 
power-presses of all countries. A recent improvement by Mr. Xorinand. 
of Paris, has corrected the irregularity, and given to this mechanism, 
which, for rapid printing, is preferable to either of those above described. 
a greatly increased value. 

In order to understand this improvement, it is necessary to consider 
the cause to which the periodical inequality above spoken of is oat in g. 
The universal joint, commonly called Hooke's joint, in England, and 
Cardan's joint in France, may be conceived of by supposing the adjacent 



PRINTING PRESSES — NORMAND's IMPROVEMENT. 435 

ends of the two arbors which it is to unite to be provided each with an 
attachment in the form of the semicircuinferen.ee of a circle firmly con- 
nected with the arbor by its middle point, and both pivoted by their 
extremities to the arms of a rigid equal-armed cross. If the two arbors 
are in the same straight line, they will revolve together with equal angular 
velocities ; and the semicircumferences will generate in the revolution 
the surface of a sphere. If, however, the arbors are inclined to each 
other at any angle, each will generate the surface of a hemisphere, and 
the bounding circles of these hemispheres will intersect at an angle equal 
to that made by the arbors. Supposing the arbor to lie in a horizontal 
plane, and the movement to begin when the plane of the semicircle on the 
driving arbor is vertical, the angular velocity of the arbor which is driven 
will be for the moment less than that of the other. Let the upper ex- 
tremity of that arm of the cross which is vertical in the position as- 
sumed, be called A, and that extremity of the horizontal arm which in 
the order of movement follows this, be called B ; then, while A advances 
through any small angle, ^, B will describe a lesser angle V 7 . This will 
be evident by supposing a great circle of which B is the pole to pass 
through A. This circle will cut off from the two bounding semicircles 
of the two hemispherical surfaces above described a right-angled tri- 
angle, of which <p will be the hypothennse, and an arc equal to $ the per- 
pendicular. Also, the angle between these two sides will be the angle 
made by the two arbors, and may be represented by u>. This construc- 
tion gives immediately, 

Cos w—cot y tan i> ; or tan <p cos w=tan ^. 

So long as cos a> is less than radius, therefore — that is to say, so long 
as there is any inclination between the arbors — tan <p will be greater 
than tan f. When <$ becomes equal to 90°, both tangents become in- 
finite, or ^=90° also. In the second quarter of a revolution, V exceeds 
cp, and the two arcs become equal again at 180°. The relative values 
of the two angles in the third quadrant correspond to those in the 
first, and those in the fourth to those in the second. It appears, there- 
fore, that when the point which we have called A is in its highest or in 
its lowest position, the angular velocity of the driven arbor is at its 
minimum 5 and that when this point is in the horizontal plane passing 
through the arbors, the same velocity is at its maximum ; the velocity 
of the driving-arbor continuing in the mean time to be uniform. There 
is, accordingly, an intermediate point in every quadrant at which the two 
velocities are equal. The improvement of Mr. Xormand consists in giv- 
ing to the pinion which moves the table of the press a figure departing 
from the circular by a law corresponding to that which governs the 
angular velocity, in such a manner that, when this velocity is above the 
mean, the radius of the pinion which is at the moment engaged with the 
rack is to the same degree below the mean, and vice versa. The recti- 
linear velocity transmitted to the table is, therefore, uniform. The figure 



436 PARIS UNIVERSAL EXPOSITION. 

of the pinion is approximately but not exactly elliptical. It remains 
only to be observed, that in order to give steadiness to the pinion, the 
racks into which it gears are made undulating, being depressed where 
the longer radii come into action, and elevated to meet the shorter. 

This form of movement was illustrated in the Exposition by very fine 
presses of Mr. Alauzet, and others of Messrs. Perreau & Co., of Paris. 
One of the presses of Mr. Alauzet was what is called by the French a 
reaction press. By this it is meant that the cylinders turn alternately in 
opposite directions, and that impressions are taken both in going and in 
returning. These presses are made with two, four, and six cylinders, 
throwing off from four to eight thousand sheets per hour. 

COLOR PRINTING: PRESSES. 

Messrs. Koenig & Bauer, of Bavaria, mentioned above, exhibited an 
interesting press designed for printing in two colors at one operation ; 
an effect accomplished by passing two forms successively under the 
same cylinder. The cylinder accordingly makes two revolutions before 
giving up the sheet. A press of similar description was also exhibited 
by Mr. Dutartre, of Paris. In one of these machines an expedient was 
employed to secure perfect equality of pressure upon the two movable 
tables on which the forms repose, or to increase the pressure upon one 
in case a larger or more continuous surface of type should require it, 
consisting in a construction resembling a pair of wedges reversed upon 
each other. This permits an elevation or depression to be made in the 
most gradual manner, without in the slightest degree disturbing the 
level. In a press of Mr. Dutartre, designed for printing works of ele- 
gance, the cylinder admits of being thrown out of gear, so that the 
same sheet may be twice impressed before being removed. In this ma- 
chine the inking-rollers are driven by a system of wheels, and not by 
the pressure of the type. 

ROTARY PRESSES. 

liotary or continuously acting presses, in which the form is adapted 
to one cylinder and the pressure is applied by another re vol viug against 
it, were exhibited by Mr. Alauzet, Mr. Marinoni, and Mr. Derriey, all of 
Paris. The last two exhibitors presented presses with two type 
cylinders, which were, therefore, also presses a ret (ration, or designed to 
print the sheet on both sides before giving it up. 

No foreign presses constructed on the continuously rotary system have 
yet, however, equalled those of the originator of the system. Mr. Hoe. of 
New York. It was a subject of regret that none of Mr. Hoe's presses 
were on exhibition in the Exposition. Presses constructed in his own 
workshops are now in use in many of the principal newspaper offices ot 
Great Britain, and have long been so. It is an interesting fact in the 
history of this subject, that, on the first introduction of these machines 
Into England, English workmen were employed by most purchasers in 



EOTARY PRINTING PRESSES. 437 

their construction ; but that, after some experience with these, they were 
found to perforin so much less satisfactorily than those constructed by 
Mr. Hoe himself, as to leave the monopoly of the market almost 
exclusively in his hands. 

THE BULLOCK PRESS. 

The most remarkable, however, of all printing presses hitherto invented 
is one which was not present in the Exposition, and which was unknown 
to the reporter until after the preparation of these notices had been com- 
pleted, and after his return to this country. This is the " Bullock press," 
so named from the inventor, the late William Bullock, of Philadelphia. 
Like the Hoe press it carries the forms upon the cylinder, but it differs 
from that press in requiring no attendants to feed it, and in delivering 
the sheets printed on both sides. It is a great improvement also, real- 
ized in this press, that the sheets are delivered silently, the noisy racks 
of the Hoe press being wholly dispensed with. 

The substitution of an automatic system of feeding for hand-feeding, 
which is one of the greatest economical advantages of this press, has 
been effected by introducing the paper into the machine, after it has 
been subjected to a moistening operation, by passing through a shower 
of fine spray, in the form of an endless roll. A single roll will contain 
several thousand sheets, and the printing operation, including the cutting 
of the paper into proper lengths, will proceed uninterruptedly until the 
roll is exhausted. 

In the following extract from the Scientific American of December 7, 
1867, the advantages of this press are more fully set forth: 

"The operation is very simple. The roll of paper having been 
mounted in its place, the machinery is started, unwinds the paper, cuts 
off the required size, prints it on both sides at one operation, counts the 
number of sheets and deposits them on the delivery board, at the rate 
of eight thousand to fourteen thousand per hour, or, counting both sides, 
at the rate of sixteen thousand to twenty-eight thousand impressions. 
The labor is only that of placing the rolls on the press and removing 
the printed paper, ivhich ordinary hands can do. 

u We have seen some most excellent book printing done on the Bullock 
machines, which are at work in the government office in Washington. 
They are also employed in some of the prominent newspaper offices in 
Philadelphia and New York. At the Sun office, in this city, the Bul- 
lock presses have been in use for a longtime in turning out the immense 
daily edition of that paper. Two more presses, the same kind, but of an 
enlarged and superior pattern, are now being introduced there. 

"The Bullock press promises to effect a considerable revolution in the 
art of printing. * * * Its capacity for the rapid production of 
printed sheets is unequaled. Its first cost is comparatively small. But 
a small place or room is necessary for setting it up. The largest size 



438 PARIS UNIVERSAL EXPOSITION. 

is eleven feet long, six feet wide, and seven feet high. Only two hands, 
common laborers, exclusive of pressmen, are required for its manage- 
ment. Being simple in construction it is not liable to get out of order, 
and can be easily repaired. 

" We have seen an official report, by O. H. Eeed, superintendent of the 
press room in the Government Printing Office at Washington, made to 
John D. Defrees, Congressional Printer, in which he shows that it would 
require eighteen of the Adams presses to do the same amount of book- 
work now being executed on a single Bullock press ; and that the use 
of this press effects a net economy of $375 a week, over such Adams 
presses. The Bullock press prints two hundred thousand octavo pages 
in a single hour. It runs with great steadiness and uniformity, and the 
number of spoiled impressions averages only about one-tenth of one per 
cent. The estimated average of spoiled sheets on the common fast 
newspaper presses is between one and two per cent. The ordinary 
presses require of the paper manufacturer that before delivery he shall 
cut his goods into sheets, count, wrap, and tie them up, in separate bun- 
dles. All this consumes much wrapping paper, twine, and time, which 
is saved by the use of the Bullock press, as the paper is delivered in 
rolls just as it naturally issues from the paper-making machine, and the 
paper-maker is enabled to supply paper for these improved presses at 
from one to two cents a pound cheaper than ordinary paper. The Bul- 
lock press prints with a perfect register, and for newspaper work this 
is important, as it permits the reduction of the blank margin of the sheet, 
and thus saves paper. 

" Altogether, the advantages and economies in favor of these new 
machines are so great that, in many cases, printers might, by adopting 
them, be enabled to throw away their present cumbersome presses as 
old iron, and make a very large annual profit by the operation. Think 
of saving $5,000 on the press- work of a single job. This is the state- 
ment from the government office in reference to the printing of the 
volume of the Agricultural Eeport, which was printed on a Bullock 
press." 

The New York Herald, the New York Democrat, and the Philadelphia 
Democrat, as well as the New York Sun, mentioned above, are now 
printed on the Bullock press ; and it is probable that this great inven- 
tion, which has given universal satisfaction wherever it has been intro- 
duced, will soon, for rapid printing, supersede every form of press at 
present in use. 

NUMBERING- PRESSES. 

Presses for printing numbers upon bank notes, railroad tickets, bonds. 
&c, were numerously represented in the Exposition, and attracted much 
notice from the curious ; but none of these presented anything which 
could be called new in principle. Some of them were designed to num- 
ber objects already printed, and others to print and number simultanc- 



NUMBERING PRESSES — DRESSING TYPE. 439 

ously. In the latter case it is necessary that the numbering apparatus 
be sufficiently compact to form a convenient combination with the type 
employed in printing the body of the impression, and that it shall be 
truly adjusted to the same level. By a recent improvement of Mr. Der 
riey, the numbering rollers are prepared by casting, instead of being 
cut by hand, thus insuring perfect uniformity in the character. One 
machine constructed by this gentleman for the use of the Bank of France 
in numbering its notes, presents some features of special interest. Each 
note receives five impressions from the machine at once, distinctive of its 
relations to the remainder of the issue. One of these is simply it's num- 
ber of order, and increases from note to note ; the others are significant 
of the class or of the particular series to which the note belongs, and 
change with the commencement of each new series. But the ingenious 
part of the contrivance is that by which it is made entirely automatic, 
taking up each note separately from the supply on one side, transport- 
ing it to the printing table to be stamped, and subsequently removing it 
and depositing it in the receptacle for finished notes. The notes are 
lifted by a gentle force of aspiration or exhaustion, acting through a 
hollow plate perforated on the under side, and having a regular succes- 
sion of movements. The exhaustion is produced by a small air pump. 
Other applications of this ingenious principle have been elsewhere 
noticed in this report. 

DRESSING TYPE. 

An illustration of the fact that serious difficulties in the progress to 
perfection of the most important of the arts of industry are often found 
in matters of detail which escape the popular notice, is afforded by a 
machine presented in the American department by Mr. P. Welch, of 
New York, for dressing the surfaces of type. The types, as they come 
from the mould, have certain irregularities which require to be removed ; 
and in removing these it is of the highest importance that the perfect 
parallelism of the opposite surfaces should be preserved, as well as the 
exact equality of depth in the direction of the character, so that, as set 
in the form, they shall constitute a perfectly compact mass. This finish- 
ing of type has never heretofore been conducted by any process insuring 
precision. The method universally practiced has been to rub the pieces 
of metal by hand upon the plane surface of a stone, employing also as 
auxiliary a scraper or file. The operation is wanting in expedition, and 
is attended with loss, since many types are inevitably spoiled in the 
process. The invention of Mr. Welch has entirely superseded the 
necessity of further using so rude an expedient. The types are supplied 
automatically and finished with great rapidity and the most perfect 
uniformity. 

Some notion of the manner in which this machine operates may be 
gathered from the following statement, transcribed from a newspaper 
report of an occasional visitor to the Exposition : 



440 PARIS UNIVERSAL EXPOSITION, 

" Mr. Welch, sets liis rough type in lines intersected by strips of brass, 
and composes a square block of type to be operated upon by the machine. 
The dressing-machine passes each single row of types between a pair of 
knife-blades, set exactly parallel to each other, and ground rectangular 
or taper, as the case may be, for the production of square type or pyra- 
midal type, the latter suitable for being set up on a cylinder for a roller 
printing-machine. The type, being pushed through between the fixed 
cutters, remains in a straight line, while the brass strip, now no longer 
wanted, drops through an opening into a box below the table. The dif- 
ferent rows of type being dressed on two parallel sides, now form a 
square block without partitions, and can be divided into straight lines 
in the second direction, presenting the two still undressed edges to the 
action of the cutters. They are then passed through the machine a 
second time, and come out finished and set up complete, ready for the use 
of the printer. It is well worth seeing this cleverly designed machine, 
with its excellent workmanship and thorough mechanical construction 
of all its details, and to watch its operations as it goes on with regu- 
larity and precision, doing one day's work of a practiced hand in about 
one hour, with greater regularity, less waste, and a better quality of 
work produced." 

It will occasion no surprise to state that Mr. Welch received for this 
invention a gold medal, the only recompense of the first order given to 
his class, when it is remarked that the object which he has so success- 
fully accomplished has been unavailingly pursued more or less con- 
stantly by many ingenious men before him ever since movable type 
began to be used. 

PRINTING without ink. 

A little machine designed for printing letter-heads, visiting cards, and 
other such small affairs, exhibited by Mr. Leboyer, of Paris, attracted 
an attention out of all proportion to its importance, in consequence of 
the fact that its impressions are made without the visible use of ink. 
It is but a mechanical application to typography of the principle of 
the reporter's multiple writer, referred to further on, in speaking of 
Flamm's typographic compositor. The ink, or the coloring matter 
which answers for ink, is contained in a thin sheet of porous paper, 
which is introduced between the type and the card or paper on which 
the impression is to be made. The machine itself is a greater curiosity 
in a. mechanical point of view than its performance in a chemical. In 
dimensions it is but about two feet by one in plan, and a foot and a half 
in height ; and the celerity of its operation is so extraordinary that it 
throws off not fewer than one hundred cards per minute. 

GILDING AND BRONZING OF CHARACTERS. 

The bronze letters and figures upon the bonds of the United Srates. 
and other similar prints, are produced by applying the metal in fine 



GILDING AND BRONZING STEREOTYPING. 441 

powder or dust to the surface of the letters as freshly printed with 
ordinary printing ink, or with drying oil simply, and brushing off the 
excess. This operation is ordinarily performed by hand, as at the 
Treasury Department of the United States^ and is accordingly by no 
means rapid. A machine was exhibited in the French department of 
the Exposition for doing the same thing mechanically and with great 
rapidity. This machine consists of a cylinder completely enclosed in a 
box, with the exception of an opening for the introduction of the sheets. 
The sheets are seized by metal fingers attached to the cylinder, as in a 
printing press, and brought by the revolution into contact with a second 
cylinder constructed of elastic material, of which the lower surface is 
immersed in the bronzing powder. After passing this cylinder, a 
revolving brush removes the excess of powder, and other cylinders com- 
press the sheet and give smoothness or polish to the metallic coating. 

IL—STEBEOTYPIKG. 

It has added incalculably to the value of the Hoe press that a pro- 
cess of rapidly stereotyping cylindrical forms, adapted to their cylin- 
ders, has come into use within the past ten or twelve years, by means 
of which a number of distinct advantages have been simultaneously 
secured. It was, in the early history of this very ingenious machine, 
one of the most difficult mechanical problems connected with it to 
secure firmly to the great cylinder the ponderous u form " embracing 
the matter to be printed. This form, being made up of many thousand 
separate pieces of metal, required to be securely " locked," as, in case 
there should be anywhere any looseness, the type thus imperfectly 
secured were liable to be thrown out by the centrifugal force. The 
u chase," therefore, (or iron frame employed to hold the form,) was a 
subject of much study, and many expedients were successively devised 
to expedite and perfect the modes of locking up the forms. It would 
seem that as the outer surface of the form, or the type-face, is a part of 
a larger circle than that occupied by the base, therefore the ordinary 
type with x^arallel sides could not be used on the Hoe press. This, how- 
ever, is an error, at least when the length of the lines in the pages or 
columns is not greater than three or four inches, as is generally true of 
newspapers. By giving a certain amount of bevel to the rules dividing 
the columns, and to the " furniture" of the chase, the requisite com- 
pactness of the mass may be obtained 5 and although the faces of the 
type will not be mathematically tangent to the circle they describe, the 
deviation will not be sufficient to mar sensibly the impression. For 
longer lines, or for smaller cylinders than those constructed by Mr. Hoe 
for the daily press, bevelled type must be employed. 

By substituting stereotype cliches for forms of movable type, the 
difficulties of locking up cease to have existence. The form no longer 
consists of many pieces, but of one only, and it requires but a very sim- 
ple system of attachments to secure it to the cylinder. Moreover, by 



442 PAKIS UNIVERSAL EXPOSITION. 

the great reduction of the thickness of metal in the plate below that of 
the form of movable type, the handling of the forms becomes much 
easier, and their own weight is not likely to be the cause of accidents. 
It is also to be taken into account that a second or a third cliche may 
be obtained as easily as the first ; a very important consideration in the 
case of a publication of which many thousands have to be thrown off in 
the course of a few hours. Before the perfection of the invention of 
rapid stereotyping, the London Times was daily set up in duplicate. At 
present it is set up but once, and is stereotyped in triplicate or quadru- 
plicate, the original form of movable type not being used to print from 
at all, but only to furnish matrices for the cliches. There follows from 
this the important advantage that the type undergo but very slight 
deterioration, so that a single font will last twenty years ; when, if used 
in the impression of the paper daily, it would be unfit for use in less than 
two. And a second advantage, of almost equal value, consists in the fact 
that the paper is practically printed every day from new type, since the 
casts have all the sharpness of the original. 

The cliches which have served to produce the edition of the day, are 
of no further use when the day is past. They may therefore be broken 
up and thrown into the melting pot for the morrow, so that the same 
metal may serve, with very little loss, indefinitely. In the short space 
of two hours, between three and five o'clock every morning, there are 
prepared from the forms of the London Times, which are corrected and 
turned over to the stereotypers at the hour first mentioned, three sets of 
stereotype plates complete for the eight pages of the paper, or twenty- 
four plates in all. The paper is then printed off at the rate of between 
forty and fifty thousand impressions per hour. In the office of Le Petit 
Journal of Paris, a daily newspaper of four pages, sold at one sou, and 
of wiiich the circulation is enormous, exceeding two hundred thousand 
copies, six cliches are taken of each page, and as many presses are 
employed from four to six and a half hours in working off the edition of 
the day. It is evident that without the process of multiplying plates 
by casting, and without the rapid power-presses now in use, a limitation 
to the circulation of the most successful newspapers would long since 
have been imposed by the impossibility of further increasing the issue. 

The material employed in taking impressions of type for casting, is a 
kind of papier inaehe. It was first introduced into the office of the 
London Times ten or a dozen years ago, but seems to have been origin- 
ated independently, also, by the Paris publishers about the same time. 
Moulds in plaster had been previously used. They are easily prepared. 
but are more frail, and are slower in drying for use. The practical diffi- 
culties of preparing such moulds from curved forms, are also greater 
than in the case of the material by which plaster has been superseded. 
Stereotyping was first introduced near the close of the last century, by 
the publishing house of Firmin-Didot. The process originally employed 
by this establishment was to impress an intaglio of a page set up in type 



STEREOTYPING SWEETS MATRIX MACHINE. 443 

of liard metal upon a plate of lead, and to use this as a matrix for produc- 
ing the cliche. To this process succeeded another, in which the page 
was set up in the first instance in movable pieces, which were them- 
selves moulds and not types. The disadvautage of this process was, 
that proofs could not be taken until a cast had been made, so that if 
there were errors to correct, it was necessary to sacrifice the first cliche, 
and possibly the second. The suggestion of the improvement by which 
casts in plaster were substituted for composite moulds in metal was 
made by Lord Stanhope, about half a century ago. The substitution of 
papier mache for plaster, which has taken place within the last ten 
years, has not only greatly facilitated the process itself, but has made it 
practicable to preserve the matrices for future use, an advantage which 
could not be secured with plaster moulds on account of their fragility. 
Whatever the material employed in the formation of stereotype mat- 
rices, the first step in the process, hitherto quite indispensable, has been 
to set up the matter to be stereotyped in regular forms of movable types. 
In the present Exposition, the novelty has presented itself of a method 
of producing such matrices without this preliminary, the characters 
being impressed one by one in succession upon a plastic surface by 
means of machinery. The most remarkable machine for effecting this 
object which has yet appeared, was exhibited in the United States sec- 
tion, and is the invention of Mr. J. E. Sweet, of Syracuse, New York. 

SWEET'S STEREOTYPE MATRIX MACHINE. 

The machine of Mr. Sweet resembles somewhat, in external appear- 
ance, a parlor organ. It presents in front one or more banks of keys, 
the number corresponding to the number of characters to be employed 
in the work, with a few additional keys to provide for the spaces between 
the words. The construction may be understood by reference to the 
several figures of Plate VII. Fig. 1 represents a section through the 
middle of the machine, with the parts which are out of the plane of the 
section drawn in outline. Fig. 5 is a similar section in plan. In these 
figures the shaded parts marked A are portions of the fixed frame 
work. B B are keys of which the finger touches are marked b. These 
are pivoted near the middle of their length at ft 3 , and guided by upright 
metallic slips marked b 2 . C, in Fig. 5, seen also in section in Fig. 1, is a 
stationary disk, perforated on its limb with a number of holes equal to 
the number of characters employed, through which there slide vertically 
an equal number of pins marked &. Each one of these pins rests upon 
the extremity of one of the levers B, and is raised whenever the corre- 
sponding lever is depressed by the operator, but in its ordinary position 
does not project above the upper surface of C. In the centre of C is 
pivoted the vertical shaft D, which is free to turn, and to which is firmly 
attached the horizontal arm or cross-piece E. To this cross-piece is 
attached a bar e, which is capable of a slight movement in a vertical 
direction upon a pivot at one of its extremities, but which is ordinarily 



444 PARIS UNIVERSAL EXPOSITION. 

maintained at its highest point, as shown in Fig. 1, by means of a spring. 
The shaft D has another bearing, which is not apparent, in the fixed 
part of the frame, and is also made hollow in its upper portion to admit 
the introduction of an interior concentric shaft #, which is susceptible of 
a vertical motion. To this interior shaft is fixed a cross-bar marked G, 
which passes through a mortise in D, this mortise having dimensions 
which admit the vertical motion just mentioned to take place, but 
allowing no lateral play. The shaft #, by means of the continuation *, 
is connected with the bent lever I, which forms a knee joint with j, by 
means of which the vertical rod or punch J may be depressed. The 
spring V ordinarily maintains the parts in the position shown. 

To the upper extremity of D is fixed a type wheel, seen in section at 
H, Fig. 1. Around the circumference of this wheel are arranged the 
types ft, which are held in their grooves by means of springs W W. Each 
one of these types has a slight outward projection ft 2 , by means of which 
it is to be raised to the position shown, after having been depressed in 
the operation of the machine. 

Upon the shaft D a pulley F runs loosely. By means of a band pass- 
ing round this pulley the machine may be driven by any convenient 
motor. Two cams, dotted in at/ and/ 7 , serve to apply the force of this 
pulley to the moving parts of the machine. The cam/', encountering 
the cross-bar G, causes .the shaft #, and with it the bar G, to revolve 
uninterruptedly while the operator is inactive ; the weight of g, i, and I, 
and the resistance of the spring %' being sufficient to prevent G from 
rising. If, however, the arm E, and with it the shaft D, is arrested in 
its motion, the pulley continuing to revolve will lift G by means of the 
earn/, the lever I will turn on its fulcrum I', and in consequence of the 
straightening of the knee joint j, the punch J will be depressed. If at 
that moment there is a type beneath J, this type will be driven downward 
also, and will impress the character which it bears on its face upon any 
yielding material beneath it. 

The operation of the machine is accordingly as follows : The operator 
presses down a key B by placing his finger on b. A pin & is raised so 
as to intercept the arm E in its revolution. As the arm E strikes the 
pin, a spring which it carries drops behind the same pin and prevents 
recoil. The adjustment of the types on the circumference of the wheel 
H is such that the letter corresponding to the key touched shall at this 
moment stop under the punch J. The cam /. raising the arm G. 
depresses J through the mechanism above described, and thus forces 
downward the type beneath it upon the surface prepared to receive the 
impression. 

The material employed to form the mould or matrix is paper, resem- 
bling that which is used in the manufacture of paper collars. Several 
thicknesses of this paper are combined, in order that the impression may 
have sufficient depth. Any yielding inelastic substance may replace 
the paper for this purpose ; but as it is of the utmost importance that 



STEREOTYPING — SWEET'S MATRIX MACHINE. 445 

the successive impressions shall not disturb or distort those which have 
been already made, the substance chosen ought to be one which yields 
by diminution of volume, and not by displacement of material. A 
plastic but incompressible clay or paste is therefore not suitable for 
this process unless indeed in the case of characters comparatively 
distant from each other. 

The platen on which the prepared material for receiving the impres- 
sion is placed is represented at P P. The prepared material is firmly 
secured to the platen so that it may follow all the movements which are 
given to the latter by the machine. So soon as the impression of one 
letter has been completed, it is necessary that the mould should be so 
far displaced as to bring a fresh surface to receive the next. The manner 
in which this object is accomplished is to be now described. A roller K, 
with ratchet groves extending from end to end, occupies the whole 
length of the machine immediately behind and above the finger board, 
as shown in Fig. 5. Fig. 1 shows the projection of the same at K. Each 
one of the key levers is provided with a rod &', hinged at the lower end 
upon the lever, but resting at the upper upon the roller K, where it 
receives a form which enables it to fall into the ratchet grooves, upon 
which it acts as a driving click or pawl. L is a two-armed lever with 
circular heads, M, N, shown separately in Fig. 2. To these circular 
heads are applied metallic bands, by means of which motion may be 
imparted to the lever L by the roller K, and by the lever itself to the 
platen P through the extension N. A band, for instance, is secured by 
one end at n' and at the other at n 2 . Another is secured at ?i 4 and at n 5 . 
There are tightening screws at n 6 and ri 1 by which these bands are 
strained. A single band of the same kind is attached at one extremity 
of the lower arch head M, and passes around &', which is firmly connected 
with or is part of the roller K ; the other extremity being secured to a 
sliding block m which is acted upon by a tightening screw m 3 . It is by 
the friction of this band on ~k' that the lever L is moved when the roller 
K revolves. Motion is given to this roller as follows : 

By the depression of the key lever B, the driving click V is made to 
drop one or more notches upon the roller K. The number depends on 
the thickness of the letter which the key represents, the key B itself 
being arrested at the proper point by a fixed stop. The impression 
having been made as above described, the key B is restored to its orig- 
inal position by the action of the lever e, attached to E, which is 
depressed by the cam/ of the pulley F. The cam/ 7 , by means of which 
the impression is produced, acts during about a quarter of a revolution 
of the pulley. Immediately after it has passed, the spring i l f reacting 
upon the lever I, raises the punch J, and with it the hook j 2 , which lifts 
the type by means of the projection h 2 . This hook is secured to the 
punch J by means of the friction spring j', which is sustained by pins 
passing through J, as shown. The cam /does not act until the cam/ 
has completed its action ; but immediately afterward it forces down e 



44 ) PARIS UNIVERSAL EXPOSITION. 

and with it the pin c', thus setting* the arm E free to recommence its 
revolution. The pin c', acting on the rod or driving click b', causes the 
roller K to turn on its axis more or less according to the distance to 
which the key had been previously depressed. This motion of K is 
imparted through the double arch head lever L to the platen, by means 
of the connections above described. The roller K is prevented from 
turning backward by the guard click s, and also from advancing too far 
forward by means of a friction check at the extremity opposite to &'. 
The platen is advanced by the movements thus described sufficiently far 
to be ready to receive a second letter of a word. But in case a word is 
complete, and a blank space is necessary before commencing a second 
word, the roller K may be operated on without printing, by means of a 
set of four or five keys forming a higher bank, of which one is shown 
at E, Fig. 1. These keys have stops beneath them, marked r 2 , which 
striking K arrest farther descent. These stops are adjusted so as to 
give the different spaces required in separating words or in justifying 
lines. 

It is in the matter of justification that one of the most troublesome 
obstructions in the way of the rapid operation of this machine will be 
found. It will not answer here as in the ordinary work of composition to 
go on to the end of the line before spacing out the words. When the 
impressions have once been made, their places cannot be changed. It is 
necessary, therefore, to know in advance how much surplus space is to 
be provided for. The inventor's method of ascertaining tins is the fol- 
lowing : Each type is supposed to have a thickness equal to a certain 
number of elementary equal parts. The number of such elementary 
parts which a line will contain is found by trial, or fixed beforehand 
arbitrarily. Taking now the words of the copy which are to be set 
in a given line, we find the value of each word by adding together the 
separate values of its letters, and then add together these word values 
until we have as many as the line will receive, with allowance for space. 
The total, subtracted from the value of the line, will give the total 
amount of space to be provided for, and this divided by the number of 
spaces will give the value of each space. The inventor supposes that 
the compositor can by simple mental calculation settle this import- 
ant point as he goes on. The probability of this supposition hardly 
needs to be discussed. At any rate, considering the possibility of occa- 
sional error in such mental computations, though they should be gen- 
erally easy and exact, and considering also that errors cannot be cor- 
rected after the impression has been made, it would be safest to have the 
copy prepared and scored in advance. 

Supposing, however, that the operator has no previous indication as 
to the quantity of matter which will fill in a line, he needs to be apprised 
when he is approaching the end ; and for the purpose of giving him 
this information an index arm attached to the arch-head lever I. and 
marked I 2 traverses a graduated scale as the platen advances and shows 



STEREOTYPING — SWEET'S MATRIX MACHINE. 447 

at any moment the degree of advancement. When the line is finished, 
a handle affixed to the index arm I 2 enables the operator by lifting the 
arm to reverse the movement of the platen and place it in a position to 
commence a new line. In doing this, force enough must be employed 
to overcome the friction of the band M on W j but it is obvious that W 
might itself admit of reversal by being connected with K by means of 
a clamp. 

It is necessary, however, that the platen should not only return through 
the space by which it has been moved laterally in forming the line, but that 
it should have at the same time a longitudinal movement equal to the 
distance between two successive lines. While therefore the carriage of 
the platen N is confined by its ways to a simple reciprocating movement, 
the platen itself has a second movement at right angles to this in which 
it is guided by similar ways, as is shown at the left hand margin h of 
the section, Fig. 1. The longitudinal movement must take place during 
the return of the platen, after the completion of one line, to the position 
for commencing another. The contrivance by which this is effected 
is shown in Figs. 3 and 4. Fig. 3 is the under surface of the platen. 
Fig. 4 presents the platen in side view, the lower surface being turned 
upward. This lower surface is provided with two sets of grooves cross- 
ing it entirely ; one set being at right angles to its length and the other 
set inclined in such a manner as to connect one end of each groove of 
the first set with the opposite end of the next one parallel to it. The 
grooves are triangular in cross section, one side being vertical and the 
other inclined. The directly transverse grooves are deepest on the side 
where the line begins and considerably shallower on the opposite side. 
The reverse is true of the inclined grooves, which are deepest on the side 
where the line ends. A puppet bolt g, having a chisel-edge extremity 
adapted to the grooves, is fixed in the carriage of the platen and beneath 
it, and is held firmly in the groove in which it may at any time be by 
means of a spiral spring. This bolt is commanded at the pleasure of 
the operator by the handle #, Fig. 1. When the lateral movement com- 
mences at the beginning of the line the chisel-edge of the bolt follows 
the transverse groove which is there deepest. But when, after the com- 
pletion of the line, the ret urn movement begins, then it will be the oblique 
groove which will be followed by the edge j and as the bolt is fixed 
while the platen is movable, a longitudinal motion is the consequence, 
equal to the distance between two consecutive grooves. If this is the dis- 
tance required for the commencement of a new line, the work may imme- 
diately proceed. If not it is indispensable that it shall be at least 
an aliquot part of that distance. Suppose, for example, that a second 
line is required to be formed at a distance from the first represented by 
double the space between the successive grooves. In this case the 
required distance may be secured by moving the platen forward and back 
by means of the handle I 2 ; but this would not be possible if the distance 
required were only once and a half the same space. 



448 PAKIS UNIVERSAL EXPOSITION. 

The machine, to answer the exigencies of the art, ought to admit of 
having its types changed so as to substitute a smaller or a larger set for 
those immediately in use. In this case every change of font would 
require a change of platen ; and a simultaneous change of all the stops 
of the finger keys. In a large establishment a separate machine for 
each font would be preferable. 

The rapidity with which moulds may be formed by this machine is 
very remarkable ; provided that the copy has been scored in advance, 
this rapidity is measured only by the celerity with which the operator 
can touch the keys. The casts or cliches produced from these matrices 
are not yet, at least in the specimens exhibited, so sharp as could be 
desired. This may be owing to the imperfection of the material of 
which the matrices are formed, and since the invention is in its infancy, 
its capabilities cannot fairly be judged by its present performance. 

It is a disadvantage which may limit a usefulness promising otherwise 
to be very great, that the matrix when once formed admits of no cor- 
rection, or at least of no correction which shall involve any displacement 
of the words allowed to stand. Means might undoubtedly be devised for 
removing and replacing a line or word, provided the matter inserted should 
occupy no more, nor less room than that for which it is substituted. The 
consequence is that much of that alteration and amendment which authors 
are accustomed to defer until they see their productions in print, must 
b3 entirely completed in the manuscript, or the machine will be unavail- 
able for original publications. There are few writers who cannot accom- 
modate themselves to this necessity in regard to the bulk of a given 
work. As to those parts which must be printed before they can be per- 
fected, it would not probably be a very serious matter to sacrifice the 
first casts of such pages and construct the matrices anew. 

The machine of Mr. Sweet cannot as yet be said to have been brought 
to such a state of perfection as to justify the expectation that it will 
immediately come into general use ; but it embraces the germ of a very 
important improvement, and there can be little doubt that the art of 
printing is destined to derive large advantages from it in some form here- 
after. Should it become possible to prepare stereotype plates without 
the necessity of setting up the matter first in movable types, a very large 
reduction might at once be made in the amount of stock and furniture 
required in all great publishiug establishments. Printing olfices would 
be vastly less encumbered than at present with the quantity and bulk 
of their material ; and the amount of capital which would be necessary 
in order to keep alive an industry of given magnitude would be corre- 
spondingly diminished. These advantages are quite independent of the 
more obvious ones, which consist in reaching a given end in briefer time, 
with less labor, and with fewer intermediate steps than before : and in 
substituting for the fatiguing labor of composition with movable types, 
as at present practiced, which requires the compositor to stand from 
morning till night, the very light task of touching the keys of an instru- 
ment while sitting at his ease. 



STEREOTYPING — FLAMM's COMPOSITOR. 



449 




FLAMM 7 S TYPOGRAPHIC COMPOSITOR. 

A machine somewhat similar to that of Mr. Sweet was exhibited 
by Mr. Pierre Flainm, of Phlin, department of the Menrthe, France, of 
which the general Fig. 93. 

appearance is here 
shown. Taking ad- 
vantage of what has 
been said of the 
former one, this may 
be described in few 
words. Ithasatype 
wheel, like that of 
Mr. Sweet, and the 
types are depressed 
by a punch as in the 
same. The impres- 
sion is received upon 
a plastic substance, 

designed to form a Flamm's Typographic Compositor. 

matrix. This substance is fixed upon a platen which has two move- 
ments at right angles to each other. The principal practical difference 
between the two machines is, that the one is all but entirely automatic, 
while the other is only partially so. In the machine of Mr. Flamm, the 
type wheel is turned and the punch is depressed by the hand of the 
workman himself. The transversal movement of the platen — that in 
the direction of the line — is effected by turning a screw. But this 
movement in actual work becomes automatic. As the platen moves, an 
indicator needle moves also along a divided arc, showing the progress 
made by the platen. A certain division of this arc is fixed upon to serve 
as a starting point for the beginning of each line, and another more 
advanced division to show the end. When the needle is at the first of 
these limits, the operator turns the type wheel with his right hand. The 
upper surface of this wheel is inscribed along its limb with characters 
corresponding to the types ; and these are so placed that, whenever any 
one of them is brought to a line of verification under the operator's eye, 
the type proper to that character will be under the punch. With his 
left hand the operator then depresses a lever, which acts upon the type 
through the punch, and the impression is made. As the lever rises, the 
platen advances through a distance dependent on the breadth of the let- 
ter impressed. This movement is automatic. The operator then turns 
the type wheel again, and so continues the process. Mr. Flamm appears 
to have originally intended to make his machine more entirely self-act- 
ing. In his first constructions he employed keys ; but the manner in 
which he proposed to operate by them is not understood. In a note to 
the writer he says : "The first machines made by me were constructed 
29 i A 



450 PARIS UNIVERSAL EXPOSITION. 

with a key-board; but I was iu error iu believing that the key-board is 
the expression of celerity." 

Mr. Flamm has the same difficulty as Mr. Sweet with the matter of 
justification. His mode of proceeding is, after he has advanced in the 
line as far as he thinks it safe to go, to continue the composition without 
printing, until the needle indicates as near as possible the end of the line. 
He thus discovers, by actual trial, how much space he has to dispose of 
between the words which he has passed over but neglected to print, and 
then, starting from the end of the line, he prints these words, properly 
spaced, backward. 

The platen is then returned to its original position and is moved lon- 
gitudinally by turning a graduated disk, which shows by its divisions 
the distance moved. When this distance is that which is required for 
the beginning of a new line, the process recommences as at first. 

As an additional security against error in the movements of the 
platen, the inventor has introduced a second fixed platen outside of the 
machine, on which a point carried by tbe movable platen traces all the 
movements, so that the operator can see at any moment the line on the 
page and the point on the line at which he has arrived. 

It will be seen that the machine of Mr. Flamm is not recommended at 
all by the expedition with which it operates. It is not to be supposed 
that an operator with this machine would impress characters with any- 
thing like the rapidity with which a moderately skilled compositor will 
set up movable types. Whatever advantages it may possess, however, 
are all embodied in the invention of Mr. Sweet, which is on other 
accounts also greatly superior. It argues not very much for the dis- 
crimination of the jury, that in their awards they placed both upon the 
same footing. 

Mr. Flamm employs as the material for his matrices a kind of paste, 
of the nature of which we are not informed. It would certainly seem to 
be quite impossible to construct a matrix in the mode here practiced, 
letter by letter, in any kind of paste, without producing distortions, 
unless the spaces between the letters are made unusually Avide. The 
material chosen by Mr. Sweet seems clearly preferable. 

A A^ery important use to which the machine of Mr. Flamm has been 
applied in France, and to which Mr. Sweet's is equally applicable, is the 
preparation of impressions in a kind of transfer ink upon transfer 
paper, to be impressed afterwards on stone or on a suitable metallic 
surface, and printed subsequently in the manner of a lithograph. The 
facility with which printing from stone is now executed upon a press 
entirely similar to the ordinary letter press, and, indeed, in a form in 
which metallic types and draAvings or transfers on stone are combined, 
renders this use of these machines more likely to be immediately suc- 
cessful than that which has been described above. In fact Mr. Flamm's 
machine was first employed in t lis way for some time by the lithograph- 
ers of Nancy and Bar-le-duc; bit the tact having come to the knowl- 



COMPOSING AND DISTRIBUTING MACHINES. 451 

edge of the printers of those cities, an injunction was obtained by them 
against this employment of it, as being an infringement of their rights. 
Its success, which had previously seemed assured, was thus greatly 
impeded 5 but the injunction having been raised, it is now coming again 
into use. 

The manner of preparing the transfers above spoken of will be under- 
stood by reference to the multiple writers so frequently employed by 
reporters for the purpose of preparing several copies of a manuscript at 
once. Thin leaves of paper, charged with a species of ink or coloring 
matter, are introduced between sheets of thin and almost transparent 
writing paper, and a stylus of metal is used instead of a pencil or pen. 
In the case of the machine it is the descending type which takes the 
place of the style, and which imprints the character upon a sheet of clean 
transfer paper by pressing down upon it a superposed sheet of similar 
paper prepared with the unctuous ink which lithography requires. 

IMPROVEMENTS IN MOVABLE TYPE. 

Notwithstanding the great advantages which the stereotyping pro- 
cess offers, in respect to economy and rapidity of production, it is still 
the practice of the great publishing houses everywhere to print works 
of especial elegance upon movable types. All improvements of such 
types, therefore, which tend to increase their durability, and to insure 
the unvarying sharpness of their impressions throughout the entire edi- 
tion of a valuable work, are interesting and important. The galvano- 
plastic process of facing types with copper, an invention which originated 
in our own country, is an improvement of this description. A greater 
durability still has been more recently obtained by substituting iron for 
copper in this process ; a substitution which is effected by using as the 
electrolyte a double chloride of iron and ammonia. 

in.— COMPOSING AND DISTKIBUTING MACHINES. 

COMPOSING MACHINES. 

During the quarter of a century which is just past, a vast amount of 
ingenuity and study has been expended upon the problem of construct- 
ing a machine by which movable types may be rapidly arranged or " set 
up" for the press; yet, though the operation of setting up a single type 
is an exceedingly simple one, the proposition to arrange an indefinite 
number of different kinds, drawn from as many different depositories, in 
an order entirely arbitrary and continually varying, is one of an extremely 
complicated and perplexing character. A machine may easily be con- 
structed to perform almost any determinate single movement over and 
over again with unvarying precision. And it is not difficult to devise 
machinery to execute a system of successive movements, even though 
they may be very numerous, provided that when the series is complete it 
recurs again in the same order. In all such cases, the machine when 



452 PARIS UNIVERSAL EXPOSITION. 

once constructed will perform its functions automatically; like the differ- 
ence machine of Mr. Babbage, which, when once set according to a given 
formula, will go on turning out the terms of a numerical series so long as 
its motion is continued. A composing machine cannot be in this sense au- 
tomatic. Since the succession of the letters to be set up is independent of 
law, intelligence must direct their selection; and thus, whatever descrip- 
tion of machine may be devised to facilitate the labor of the composi- 
tor, the compositor himself cannot be dispensed with. His intelligence 
must constantly preside over the action of the machine, and every one of 
its movements must be determined by some movement of his own. The 
aim of the inventor must be, therefore, to make this movement as small, as 
light, and as capable of being executed with celerity, as possible. Some 
form of key-board solves, as far as it can be solved, this part of the 
problem. It is not very difficult to contrive a mechanism which, when 
a certain key is depressed, shall cause a single type to be delivered from 
a depository containing many of the same kind. The difficult part of 
the problem is to cause a series of types so delivered to be set up side 
by side in the order of delivery, with their faces all upward, and with- 
out any irregularity in the relative position of the characters by inver- 
sion or turning sidewise. This, it will be easily understood, where the 
number of entirely independent pieces to be transported is so great, 
and the individual pieces themselves are so small, is a very troublesome 
operation. 

In nearly all the composing machines which have yet been invented, 
the type, when set free by the keys, fall into inclined grooves or chan- 
nels in which by their own weight they descend, one after another, to 
the receptacle or composing-stick provided to receive them. They here 
form a line of indefinite length, from which they are removed in suc- 
cessive portions to a "justifying" stick, in which they are spaced out to 
the proper length of lines required. A machine of this kind was exhi- 
bited at the Paris Exposition of 1855, by Mr. Sbrenson, of Denmark : 
another by Mr. Young, of London; and a third by Mr. Deleambre. of 
France. This last was the only one of the three on exhibition in ISO 7, 
and, in fact, was the only machine of any kind for setting up movable 
types in this last Exposition. 

A machine on a similar principle by Mr. Hattersley, a British inventor. 
has not been exposed. 

MITCHELL'S COMPOSING MACHINE. 

At the London Exposition of 1SG2, a machine was shown, which 
depends for the transfer of the types upon a different principle. In 
this, each type as it is delivered from its receptacle falls upon an end- 
less band which carries it horizontally for a certain distance directly 
from the operator, or at right angles to the key-board : when it encoun- 
ters another endless band at a little lower level, which moves obliquely, 
or in the direction of the hypothenuse of aright-angled triangle of which 






COMPOSING AND DISTRIBUTING MACHINES. 453 

the first band is the base. To this second band it slides gently down a 
brass shoot, and is carried forward to a point beyond the last of the 
parallel bands, where it is acted on by a notched wheel called the set- 
ting wheel, which sets it upright and advances it to make room for the 
next type. This machine was exhibited as a British machine. It is the 
invention of Mr. W. H. Mitchell, of London, and nothing more ingen- 
ious or satisfactory could be imagined. It is the only composing machine, 
in fact, which has, as yet, successfully resolved the difficult problem 
proposed. Its merits have been practically tested in a number of large 
printing establishments, in an experience now extending to some years, 
during which it has been constantly in use. One of the most important 
of these is the establishment of John F. Trow, of New York, who has 
had five of Mr. Mitchell's machines in operation for several years, with 
constantly increasing satisfaction. 

DELCAMBRE'S COMPOSING MACHINE. 

In all these machines the types are arranged in compact rows side by 
side, and in separate but parallel channels, each row occupying a chan- 
nel by itself, and all these channels standing (except in the machine of 
Sorenseu) somewhat inclined, in one plane just behind the key-board. 
In Sorensen's machine these channels occupy the circumference of a cyl- 
inder. Generally, the action of the key displaces the lowest type of the 
column and delivers it over to the contrivance for transmission to the 
composing stick. In Delcambre's, however, the types in each channel 
are pressed upward from below, and the column has a curvature at the 
top which brings the upper end to a horizontal position. It is the most 
advanced type at this extremity of the column which is dropped under 
the action of the key. 

No composing machine can conveniently provide for all the varieties, 
or "sorts," of character which the exigencies of the typographic art may 
require. In Delcambre's machine there are eighty-eight keys, which suf- 
fice for low r er-case, capital and small capital letters, with spaces and 
points. The other characters are provided for by means of two revolv- 
ing stands, one on the right and the other on the left of the compositor. 
These are turned, as occasion requires, by hand, so as to bring the 
required sort over a guiding groove which carries it, when set free, to 
the common trunk. One such guide serves, therefore, for all the char- 
acters of each revolving stand. Of course, the introduction of unusual 
characters is not, in the use of this mechanism, an expeditious process. 
On the other hand, it is attended, in the long run, with no great loss of 
time, from the fact that it is unusual. 

A fault of all composing machines as yet invented, with the single 
exception, it is believed, of the machine of Mitchell, is that the type set 
free by the different keys do not reach their destination in equal times ; 
nor even is the time of the successive pieces from the same key quite 
invariable. The inclined planes are not all of equal length ; they neces- 



454 PARIS UNIVERSAL EXPOSITION. 

sarily cannot be all straight, and their curvatures cannot be all similar 
and equal. Moreover, from the varying condition of the surface of the 
metal, the resistance offered to gravity by friction is not constant. It 
happens, therefore, that whenever the keys are touched in rapid suc- 
cession, an engorgement occurs at some point where different channels 
join the common trunk, and annoying delay is the consequence. On 
several occasions on which the writer of this report had an opportunity to 
see the machine of Delcambre in operation this accident occurred inces- 
santly. It was no doubt occasioned by the effort to show that the 
machine was capable of performing its work much more rapidly than a 
compositor setting his type by hand ; but this was the very thing which it 
would not do. When the keys were touched slowly, and each type had 
abundant time and a clear way before it, the performance was satisfac- 
tory. The moment the celerity of movement exceeded a quite moderate 
rate, the engorgement came on, a perfect mob of type became wedged 
together in the grooves, and the work of restoring order was a seriously 
troublesome affair. 

The machine of Mr. Mitchell is free from liability to this accident. 
The endless bands move uniformly, and each type has the velocity of the 
band which carries it. The movements are so arranged that the time of 
travel of each type from the key to the setting wheel is exactly the same, 
from whatever part of the key-board it starts. Xo matter, therefore, 
with what rapidity nor in what order the keys are struck, the correspond- 
ing types will arrive and will take their places in the composing stick in 
the same order exactly, and without collision or confusion of any sort. 
The experiment has been made up to a rapidity of six touches to the 
second, or 21,600 to the hour, with the most satisfactory success. Prac- 
tically, this velocity is unnecessary. The work of " justifying n can hardly 
be conveniently divided, and the machine is not required to deliver 
the type set up any faster than they can be justified. It is stated that 
two men will set up and justify 50,000 type per day, which is about twice 
what they woidd accomplish without it. It must be observed, however, 
that the work is infinitely more pleasant and less laborious than compo- 
sition by hand. 

The above may be stated as the rate of performance of Mitchell's ma- 
chine. Sorensen claimed for his the same numbers. Of this, nothing 
positive is known. Delcambre's evidently cannot approach this, yet in 
his programme, without giving numbers, he states that his machine Avill 
perform in one hour the work of an ordinary compositor in four. 

DISTRIBUTING MACHINES. 

Every composing machine requires a distributing machine as its in- 
dispensable companion. To distribute type mechanically is a problem 
much less perplexing than to set them up in words and sentences. The 
operation may indeed be made entirely automatic. This only requires 
that each "sort" of type shall be distinguished from every other, by 






COMPOSING AND DISTRIBUTING MACHINES. 455 

some characteristic difference in the body. Such a difference may be 
provided by the following expedient. Each type in the ordinary fonts 
is marked on one side with notches, fewer or more numerous in different 
fonts, but equal in number for all of the same font; the object being to 
enable the compositor, by feeling as he picks up the piece, to know which 
side to place outward in his "stick," in order that the character may be 
erect. It is only necessary to vary the distances of these notches from 
each other, (supposing for instance that there are two only on a type,) so 
that no two pieces shall be exactly alike, and we have a means of me- 
chanically identifying every individual u sort." 

Let there, for example, be prepared a bit of metal having projections, 
or tenons, on one of its edges, corresponding exactly in size and distance 
to the notches on any type ; these tenons will fit into the notches of that 
particular letter, but will fit no other. Such a piece of metal may be 
compared to a key, and the type to a lock which it will fit. Suppose 
now that a set of such keys, corresponding to all the varieties of type, 
are arranged side by side, their projecting tenons being all slightly pressed 
against a smooth plate of metal by a separate spring behind each. Let 
then a row of type, taken from a compositor's stick, be placed in a groove 
or channel in another plate of metal, so that its outer surface is flush with 
the plane of the plate ; and let this plate be placed edge to edge with 
the former and used to push it aside, so that the lower type of the row (the 
type lying on their sides) shall pass along in front of the series of keys. 
So long as it passes keys only which do not belong to it, no consequence 
will follow; but the moment it comes opposite to its own, the tenons of 
that will drop into its notches. Thus the type is identified, and a me- 
chanical movement takes place at the same time. It is a mere matter of 
detail to contrive a mechanism which shall thereupon release the type 
identified. 

The above illustration is intended merely to make intelligible the gen- 
eral principle on which an automatic distributing machine must be con- 
structed. The principle may be applied in a great variety of modes. 
In Sorensen's distributor, the type are placed in the circumference of a 
revolving cylinder, and are carried along by the revolution of the cylin- 
der over a succession of apertures which have re-entering angles corre- 
sponclin g to the notches on the type. In this machine the type themselves 
may be compared to keys, and the apertures to the key-holes. Delcam- 
bre's distributing machine is not automatic. The type are placed in a 
long row in a channel, along which they are gradually advanced. A 
mirror placed behind the type enables the operator to read them ; and 
the distribution is effected by touching a lever which displaces the last 
type of the row, and opens at the same time the duct or slide correspond- 
ing to the character, into which the type drops. In all the distributing 
machines, the type are arranged in their separate receptacles as they fall, 
in a perfectly regular order, so that they can be transferred at once to the 
composing machine. Since each description of type has its separate de - 



456 PAEIS UNIVERSAL EXPOSITION. 

pository, there is no danger of obstruction by engorgement, such as has 
been mentioned as occurring in composing machines like Delcauibre's, 
which direct the type from many branches into one common trunk. 

IV.— GRAPHIC METHODS &KD PKOCESSES. 

PANIC O GRAPH Y. 

The preparation of plates for the letter press from zinc by processes 
chemical or galvanoplastic, or both, has recently acquired considerable 
importance. As yet it is chiefly employed for music, designs, maps, 
charts, and other objects in which extreme fineness of delineation is not 
important. The subject to be produced is prepared on transfer paper 
with suitable ink, and applied to the surface of a polished plate of zinc. 
Fine rosin is then dusted on the ink, which gives to the lines hardness 
and substance. The uncovered parts of the plates are subsequently 
eaten out by acids, and the plate is ready for the press. 

An improvement on this process is to write upon a plate of zinc with 
a kind of conducting ink, the plate being first coated with a non-con- 
ducting film, and to throw down copper afterwards upon the lines by 
means of electricity. The completion of the process consists in remov- 
ing the non-conducting coat and eating out the zinc not protected by 
copper by making the plate the positive electrode of the battery. 

Another improvement still is to coat the plate with whiting and to 
trace the design with a point through the coating. Tarnish will then 
adhere to the uncovered metal, but not to the whiting. This latter may 
then be washed off, after which the parts of the plate uncovered by var- 
nish may be eaten away as above by acids, when the design will remain 
in relief and may be printed from. 

The best example of the successful application of panicography to 
printing from the letter press seen in the Exposition, was the specimen 
of the geological map of France exposed by the Imprimerie Imperiale. 
This, though embracing but a limited portion of the entire map, was of 
very large dimensions, covering not less than one hundred and twenty 
square feet of surface, and Avas most admirable in point of beauty and 
finish. Seventeen different colors are employed to indicate in this map 
the various geological characters of different parts of the territory, and 
each of these colors requires a different plate and a separate impression. 
Several of these plates are prepared of zinc by the processes above 
described. 

PYROSTEKEOTYPY. 

Others are produced by a process called " pyrostereotypy." which 
consists in preparing a matrix by a peculiar process of burning it into 
wood, and then taking a cast of it in an easily fusible metal. In this 
operation the first step is to trace the design upon the surface of the 
prepared wooden block. The block is then placed before a machine 



GRAPHIC METHODS AND PROCESSES. 4f)7 

tool of peculiar construction, the essential part of which is a delicate 
blade of metal capable of being alternately advanced and withdrawn 
with rapidity. A jet of flame directed across this implement heats it to 
redness, and in its rapid thrust it burns away the wood before it, leav- 
ing a perfectly sharp incision. This process of engraving is not, of 
course, adapted to the production of lines of extreme delicacy, but the 
beauty of its results, as shown in the geological chart, is as undeniable 
as it is surprising. 

LITHOGRAPHY. 

The original lithographic press, commonly called the scraper press, 
is now generally abandoned. Very few presses of this kind were seen 
in the Exposition. A number of roller presses were exhibited, and were 
usually kept in operation in printing various designs in colors. 

In the roller presses at first introduced, the pressure was applied by 
means of levers and heavy weights to avoid accident to the stone from 
an unyielding resistance in case of any irregularity of adjustment. At 
present these weights are dispensed with, but a certain elasticity is given 
to the bearings of the cylinders by strong springs of metal, caoutchouc, 
gutta-percha, &c, placed behind them, or the same object is attained by 
placing similar yielding materials beneath the stones. The stone is 
adjusted to the proper level by means of screws or wedges beneath the 
bed-plate, or by a bed-plate of a wedge shape resting on a second 
one of similar form reversed, a construction which serves to expedite 
the adjustment, while it maintains the horizontal position of the bed 
unaltered. 

It would be but a moderate advantage to substitute the roller for the 
scraper, if it should still be necessary to continue to work the press 
by the unaided strength of men. In its present form, however, the 
lithographic press is as nearly automatic as the letter press. The stone 
is supplied with water as well as with ink by rollers, and the task of 
the attendants is limited to supplying and removing the sheets. 

Messrs. Kocher & Houssiaux, of Paris, exhibited a press in which the 
roller is itself the stone bearing the design to be printed. Some advan- 
tages are gained by this construction in point of compactness, and also 
in the facility of applying the water and the ink. It would also be an 
advantage still greater that the printing by means of a roller could be 
made continuous, so as to be employed for producing wall paper, &c. ; 
but a serious difficulty in the way of its general introduction arises from 
the rarity of occurrence of homogeneous masses of lithographic stone of 
sufficient size for the purpose. In view of this difficulty, the construct- 
ors above-named have turned their attention to the attempt to super- 
sede stone for the uses of this art by means of some metal possessing 
analogous properties in its relations to oil and water. In this they 
claim to have succeeded, but the success is apparently not yet entirely 
satisfactory. An account was published in 18G6 in the Genie Industriel 



458 PARIS UNIVERSAL EXPOSITION. 

of Paris, of tlie experiments of these gentlemen in this direction. From 
this account it appears that the metal employed by them is tin reduced 
to the form of thin laminae or tin foil. In their first experiments the 
tin foil was attached by glue or paste to a very smooth pasteboard, and 
the sheet thus prepared was stretched upon the cylinder of the press. 
But the cardboard was not sufficiently resisting to sustain the pressure 
long, though in other respects the results left nothing to desire. They 
then employed ordinary sheet tin (tinned iron) in place of the card- 
board, and afterwards tinned copper, but neither of these proved dura- 
ble, and they were abandoned. The substitute which was finally found 
to be successful is an alloy of lead and antimony, something like type- 
metal. Sheets prepared with this material for a backing, and with tin 
for the printing surface, are represented by the inventors to fulfil all 
the necessary conditions. 

In order to attach securely the metallic sheet to the cylinder, there is 
a narrow opening or slit, extending along the whole length of the latter, 
which is hollow, and through this opening one edge of the thin plate is 
introduced. This edge is seized and clamped by suitable jaws ; when 
the other end, the sheet having been wrapped around the cylinder, is in- 
serted through the same opening, and having been similarly seized, is 
strained round a longitudinal rod which may be turned from without, 
and which is prevented from recoiling by a ratchet. Should this mode 
of chemical printing prove to be successful, it will possess several im- 
portant advantages over lithography. The sheets being thin and light 
will be much more convenient to handle than stones. As they admit of 
being rolled, they will occupy much less space and will less encumber 
the locality. It will be much more convenient to stow them away in 
case the designs are to be preserved for future use, and to have them 
easily accessible when wanted. They will be comparatively cheap, cost- 
ing only according to their weight, while their total weight is much less 
than that of stone; whereas stones of large dimensions are dispropor- 
tionally expensive. They may be constructed of any size, while to the 
possible size of lithographic stones there are natural limitations, and the 
rare occurrence of very large masses presenting surfaces of uniform 
character in this material practically restricts these limits very essen- 
tially. These are great advantages ; but more than two years having 
elapsed since the publication above spoken of without having secured 
for the improvement a recognized place in this important branch of in- 
dustrial art, it is to be presumed that the anticipations of the inventors 
have not been fully realized. 

In the catalogue of exhibitors as at first prepared there appeared the 
name of another projector of Paris, who proposed to himself the same 
problem which had occupied Messrs. Kocher and Houssiaux. as above 
described, viz, that of chemically printing from metal. His name having 
been withdrawn, an inquiry was instituted which elicited the informa- 
tion that his failure to appear had been occasioned by an unanticipated 



GRAPHIC METHODS AND PROCESSES. 459 

imperfection in the mechanical construction of the machine which he 
had designed to exhibit. He proposed however to make, at a later 
period, a full demonstration of the merit of his invention in presence of 
the commission of the United States. But it was only a short time 
previously to the final closing of the Exposition that he was able to an- 
nounce his readiness to furnish the proposed illustration, and no oppor- 
tunity occured to take advantage of his proposition. 

METALLOGRAPHY. 

Mr. Yerney calls his process "metallography." He proposes to print 
by chemical means from metal rollers. The following statements are 
given in his own words, (translated:) 

" The chemical process employed to fix the design so as to render 
the reproduction possible is very simple. The preparation of the me- 
tallic surface is accomplished by mechanical means specially devised 
for this object. The impression can be continuous, or upon separate 
sheets, which allows the printing of figured papers or tissues, as well 
as of pictures and every species of ordinary impression. The different 
parts of the machine are entirely new both in form and purpose. 

" The invention has been patented in France, Belgium, the United 
States and England. It has not been employed industrially beyond the 
premises of the inventor. The advantages are, besides that of continu- 
ous impression, just indicated, first, extreme simplicity; second, facility 
upon the same machine of enlarging the form ; third, possibility of vary- 
ing the forms and the different organs in such a manner as to adapt these 
machines to the most varied industries — to the printing of ribbons, for 
instance, by a machine which would not occupy more room than a sew- 
ing machine ; fourth, extreme rapidity in changing the designs ; fifth, 
noiseless movement ; sixth, lightness of construction; seventh, motive 
power, so to say, nothing; eighth, absence of all danger to the attend- 
ants. 

"The economical advantages are, in the first place, a saving of more 
than ninety-five per cent, in the cost of material merely. Lithographic 
material is expensive, bulky, very heavy, very difficult to manage, and 
very easy to break. This last accident involves also the loss of the 
design. Metallographic material, on the other hand, costs little, fills 
little space, is light, easily managed, not easily injured, and in case of 
possible injury, retains still an intrinsic value. Lithographic stones are 
limited in size, and beyond certain dimensions impossible indeed to find. 
And apart from the price, which for large stones is enormous, all the 
other inconveniences mentioned above become more serious as the dimen- 
sions are increased. In the case of metal there are no limits to the size, 
and the price is proportioned constantly to the weight. No description 
of this process has been made public." 

The inventor explains more fully that his reason for avoiding all pub- 
licity in regard to his process, has been his desire to bring it before the 



460 PARIS UNIVERSAL EXPOSITION. 

world only when every mechanical and chemical difficulty in the way of 
its success should have been successfully and completely solved. It 
cannot be denied that if his claims shall bear the test of experiment in 
their application to the actual uses of industrial art, his invention will 
prove to be, as he predicts it will, "the starting point of an entirely new 
impulse in this branch of industry." 

CONTINUOUS PRINTING FR03I ENGRAVING ON 3IETAL. 

An interesting process considered in an economical as well as in an 
industrial point of view, was presented by Messrs. Godchaux and Co., of 
Paris, in the impression from engravings executed upon metal rollers, 
of copies for children's writing books, made upon endless paper received 
from a feeding roller. The paper is impressed on its opposite sides by 
two rollers successively, and is then cut off into sheets by a knife resem- 
bling those used for the same purpose in the continuous manufacture 
of paper. After the impression the paper passes over a small gas furnace 
which completely dries the ink. This ink appears to be a water ink, 
which not only facilitates the drying, but also gives the copy the appear- 
ance of having been written with the pen ; a circumstance which, con- 
sidering the purpose for which it is intended, is a material advantage. 
The writing books, which are really elegant productions, are done up in 
covers of colored paper embellished or bearing instructive lessons, and 
a single book of twenty pages is sold for little more than one cent. 

LITHOGRAPHIC PRINTING ROLLERS. 

One of the greatest difficulties encountered in the early history of the 
lithographic art, and one which seriously, for a time, impeded its success, 
was the imperfection of the means available for applying ink to the 
stones. The printing press had long been supplied with excellent ink- 
ing rollers, in the manufacture of which the essential ingredient employed 
is glue. But the necessity of keeping the stone constantly wet rendered 
the use of this material for lithography impossible. The inventor of the 
art, Senefelder, first made use of the old-fashioned inking ball : but the 
effect was not good. He adopted, subsequently, the roller : but his rol- 
lers were imperfect. 

The house of Schmautz Brothers & Jaccpiart, of Paris, is that which 
at the present time produces the rollers most approved by lithographers, 
and supplies most of those in use in the principal cities of Europe. The 
founder of this house, and the father of the brothers Schmautz. may be 
said to have been the first to bring the manufacture to a condition at all 
satisfactory. A note from these gentlemen supplies some entertaining 
information connected with the history of this subject. They write : 

"The Count de Lasterie, who founded the first lithographic in Taris. 
imported his rollers from Germany. They were covered with a very thin 
leather, as thin as a kid glove, and lasted but a little while — about throe 
months- This very delicate leather, sewed over and over, made a seam 



GRAPHIC METHODS AND PROCESSES. 461 

too prominent, which marred the inking. When the seam began to fail 
it was the femme de chambre of Madame la comtessc who was charged with 
the duty of repairing them with her needle. This not very agreeable 
task led her to look around for some one to do it for her; and the father 
of the writer, who was then a working shoemaker, living in the same 
building, 4 St. Germain street, commenced repairs, which soon, with the 
aid of the advice of the Count de Lasterie, changed completely the fabri- 
cation of the rollers. 

u He caused leather to be prepared expressly for this work, stronger, 
yet quite as soft as before, and replaced the seam by a juncture of the 
edges. Then, instead of nailing the leather on the ends, he punched holes 
and passed through them a double cord, which allowed the leather to be 
tightened or loosened according to necessity, and the nails no longer 
wounded the hands of the printers. The roller was, therefore, finally 
born. The reputation of this roller was promptly spread abroad, and soon 
Germany, the cradle of the art, sent numerous orders for rollers to the 
writer's father; for the Germans found his rollers much superior to their 
own. Lithography rapidly spread itself over the entire world, and the 
promise of the Count de Lasterie, who had said in the beginning, i these 
rollers are a certain future for you, 7 was realized. 

"The writer's father tried various expedients in the hope of getting 
rid of the seam. He skinned the legs of calves, cows, and horses ; but 
these skins abandoned with difficulty their conical shape, so that the 
rollers were loose at one end and tight at the other. He employed also 
the skins of dogs, which gave a better result; but the mamelons produced 
prominences, and he was compelled to give them up. A joint, firmly 
made and carefully managed by the printer to prevent scratching, was 
always greatly superior. He made, also, trials of rollers composed of 
disks of leather pressed between two plates of iron and turned in a 
lathe. When a perfectly true surface had been obtained it was applied 
to the ink; but these disks, however closely pressed, left their marks 
upon the stone. It was impossible to employ them with success. The 
same failure followed experiments with various glues proposed by Mr. 
Constant, chemist at Sevres. The leather was cut to a bevelled edge, 
the two edges overlapped and united with these glues, and the joint 
kept under pressure till it was entirely dry; but on putting it to use it 
began in some days to give way in places, and soon after the whole joint 
failed. 

u Ti^ ro Hers manufactured at present last at least three years, and, 
in the hands of a careful workman, six." 

The length of this extract is justified by the light it throws upon the 
many difficulties which attend the progress of industrial improvements 
in matters apparently of the simplest nature. A great art, capable of 
applications of almost incalculable importance, was retarded in its early 
progress, not less by purely mechanical difficulties of the most seemingly 
trivial character of which the world knew nothing, than by the embar- 



462 PARIS UNIVERSAL EXPOSITION. 

rassments inherent in the nature of the process itself, and which every- 
body could see and understand. The house of Schmautz still maintains 
the pre-eminence in its own line of production which its founder early 
secured for it; and its present representative is justified in the pride with 
which he remarks, "we believe that we can affirm that the largest part 
of the lithographs exhibited in the Exposition, as well of foreign coun- 
tries as of France, have been printed by means of our rollers." 

ENGRAVING — POET-PANTOGRAPH. 

Some processes of engraving, dependent principally upon mechanical 
or chemical principles, were exhibited which seem to possess sufficient 
interest to deserve mention. One of these was a "poly-pantogrwphef 
exhibited by Mr. G-avard, of Paris, in the French section. By means of 
this ingenious instrument a multitude of perfectly similar designs may 
be simultaneously executed upon a metallic plate from a single pattern. 
In this way may be obtained, and for many purposes quite as satisfac- 
torily, a uniformity of impressions which is ordinarily secured only by 
the use of the roller die. But the peculiarity which evinces the greatest 
ingenuity in the construction of this machine, is its capability of tracing 
its multiple designs upon a cylindrical surface, though the given pattern 
should be plane. Eollers for continuous printing, whether upon paper 
or upon cloth, may thus be prepared by means of it with the utmost 
facility, the points of the gravers returning at the end of the revolution 
to the place of starting with the utmost precision, and thus producing a 
pattern completely unbroken. The adjustments are such, moreover, as 
to admit of a variation of the scale so as to produce copies either enlarged 
or diminished, or with unequal variations in co-ordinate directions, elon- 
gating or compressing the pattern at pleasure. 

ENGRAVING BY ELECTRICITY. 

Another mode of mechanical engraving was exhibited by Air. Gaiffe, 
of Paris. The machine of Mr. Gaiffe consists essentially of two or more 
disks with their faces in the same vertical, and their axes in the same 
horizontal plane. One of these disks carries the pattern to be copied, 
the others are designed to receive the engraved copies. The graving 
tools are armed with diamond points and are governed in their movements 
by the power of electro-magnetism. Each one of these implements is in 
fact connected with the armature of an electro-magnet, which, when in 
action, prevents the tool from touching the plate, but which releases it 
when the current is broken, permitting the graver to take the metal. 
These alternations of movement are determined by the pattern-plate, on 
which a conducting point is constantly resting. Both the pattern-plate 
and the plate to be engraved are in constant revolution with equal angu- 
lar velocities, while, at the same time, the tracer and the graver approach 
very gradually and uniformly toward their centres of motion. The com- 
bination of these effects causes the tracer to describe a spiral of very 



GRAPHIC METHODS AND PROCESSES. 463 

close involutions on the surface of the plate on which it rests. During 
the flow of the electricity, the tracer and the pattern-plate form a part of 
the circuit. The current will, therefore, be broken by any non-conduct- 
ing surface interposed between them. Accordingly, if a design be drawn 
upon the pattern-plate in non-conducting ink, the graver will be released, 
and will act on the metal before it every time the tracer crosses any one 
of the lines of the design. When the tracer has, in this manner, passed 
over all parts of the pattern from the circumference to the centre, a com- 
plete copy will be found to have been produced, on the plate under the 
graver, from which may be printed fac similes of the original design, 
with the exception that the hair lines will be found to be made up of a suc- 
cession of minute dots. It is easily seen that a multiplicity of copies may 
be taken simultaneously with the same facility as one. And, by the 
application of the pantographic principle, the designs may be reduced 
or enlarged in any proportion. But the method is much better adapted 
to reductions than to enlargements, inasmuch as, in proportion to the 
magnitude of the copy, the separate touches of the graver are more or 
less conspicuous. When these are very apparent the effect is by no 
means pleasing. The spiral arrangement of the minute touches becomes 
apparent, and the impression produced upon the mind is that of a me- 
chanical rather than of an artistic triumph. The pattern best suited to 
elegant reproduction by this process is formed by taking a plate already 
nicely engraved and filling its lines with resin. If the pattern is large 
and the copy small the prints from the reductions are very pretty. 

It is easily seen that reductions to different scales may be simul- 
taneously made from the same pattern. If a series of gravers be attached 
to a bar, pivoted at some point in the line of the centres of motion of the 
revolving plates, their points being all truly in line with this pivot and 
and with the tracer, then in the gradual movement of this bar on its 
pivot, copies will be executed to scales greater or smaller, in proportion 
to their distance from this point. 

At the Exposition of 1862, in London, a machine for engraving by 
electricity very similar to this was exhibited by Mr. H. Garside, of Man- 
chester. It was said to be a French invention and may have been the 
same ; but it was there employed only for the purpose of preparing rol- 
lers for printing tissues and paper hangings. 

DULOS'S METHOD OF ENGRAVING. 

Another novel method of engraving, essentially chemical, was exhibited 
by Mr. Dulos, of Paris, and was rewarded with a medal of gold. In this, 
the subject to be copied is first produced in lithographic ink upon a surface 
of copper. The parts uncovered by the ink are then coated with iron 
by the galvanoplastic process. A solvent is next employed to remove the 
ink, and the copper surface thus exposed is silvered by electricity. Mer- 
cury being then applied to the silver, there is formed an amalgam which 
presents the design in relief. From this relief a cast is taken, after which 



464 PARIS UNIVERSAL EXPOSITION. 

the remaining steps of the process need no explanation. The process 
furnishes plates adapted to the copper-plate press or to the letter press, 
as may be desired. Specimens of impressions from plates thus prepared 
were on exhibition, and appeared to be admirably executed. 

HELIO GRAPH Y. 

Since the invention of the pnotographic art two objects have steadily 
occupied the attention of those experimenters whose attention has been 
given more to the improvement of the art itself than to its practice as an 
industry. The first of these is the production of pictures presenting not 
merely the forms, but also the natural colors of visible objects. To a cer- 
tain extent the persevering efforts which have been put forth in this direc- 
tion have been crowned with success. Photographic proofs representing 
objects in their natural colors were exhibited by Mr. Xiepce de St. Victor, 
a gentleman whose name, as well as that of his distinguished relative. Mr. 
Mcephore ]Slepce, will ever be intimately associated with the history of 
this beautiful art ; but these colors are unfortunately fugitive and shortly 
disappear on exposure to the light of day. To have produced them at 
all is, nevertheless, a great step of progress. It can hardly be doubted 
that expedients may yet be devised by which to fix the tints which have 
been hitherto found to be so fleeting. 

The second of the objects above referred to is that of impressing upon 
metal or upon stone the images of the camera so forcibly as to allow 
prints to be taken of them in ink, which, as it respects beauty and 
minute accuracy of delineation, may be in some good degree comparable 
to the photographs themselves. This very important object may be said 
to have been more satisfactorily attained. For many purposes, light ful- 
fils perfectly the functions of the burin upon metal, or of the pencil upon 
stone. In the reproduction of the delicate gradations of shade which 
characterize the photographs of natural objects, something remains per- 
haps yet to be accomplished; but copies produced from actual engrav- 
ings, in which such shades are imitated by the greater or less force of the 
lines or dots employed to express them, are so faithful to the originals 
as scarcely to admit of being distinguished from them. 

The earliest attempts at heliography date almost as far back as the 
invention of the daguerreotype, and were made upon the daguerreotpye 
plates themselves. At this period of the history we meet with the names 
of Donne and Berres, experimenters who endeavored, by the use of 
dilute nitric acid, to bite in the dark parts of the picture; while the 
light parts being covered by mercury, should be left untouched. Since 
mercury is soluble, however, as well as silver in the acid, it results that. 
if the operation is long continued, the whole surface becomes at length 
uncovered, and the biting ceases to be differential. And if the process 
is arrested before this effect has been produced, the impression is not 
sufficiently strong to produce satisfactory prints. 

Mr. Grove, and afterwards Mr.Fizeau, proposed an improvement of this 



HELIOGRAPHY, FIZEAu's PROCESS. 465 

method which was attended with better success. The mordant employed 
by these gentlemen was aqua regia, but this may be replaced by a mixed 
solution of alkaline salts of the component acids. A chloride of silver 
is formed upon the darks which may be removed by solution in caustic 
ammonia, and the process may then be repeated. By this means an in- 
equality is produced which suffices to enable the operator to protect the 
more prominent portions of the plate by electro- gilding, the depressions 
being preserved from the action of the battery by means of a coating of 
oil. After the gilding, the oil is removed by caustic alkali, leaving the 
copper in the depressions exposed to the action of chemical reagents, 
while the prominent portions are perfectly protected by their covering 
of gold. The etching may then be carried to any extent desired. 

A defect of the plates thus produced, and it is one which still exists 
in those which are formed by more recent and more perfect processes 
when the photographs from which they are derived are such as have 
been taken directly from natural objects, is that the uniformity of sur- 
face upon the deep shades is unfavorable to the adhesion of the ink. 
To overcome this difficulty the expedient has been resorted to which 
is commonly employed in the preparation of aqua tint engravings — 
that is to say, before applying the mordant the plate is dusted over 
with finely powdered resin. This, by producing inequalities of action, 
leaves the surface sufficiently rough to retain the ink. A variety 
of other expedients to the same end have been introduced by more 
recent experimenters, none, perhaps, yet entirely satisfactory. 

With this reservation, it may be said of the plates engraved by the 
process of Mr. Fizeau, that the prints which they furnish are excellent ; 
but the softness of the metal restricts very much their durability, and 
they allow but few copies to be taken. They may be made more lasting 
by being coated electrically with copper ; and with this improvement no 
doubt they would continue to be used, but for the fact that more recent 
and less uncertain methods of operating have superseded this one, and 
left to it only a place in history. 

The processes at present in use, which are considerably varied, depend 
upon one general principle, which is to spread over a plate of metal a 
thin coating of some substance which, from being originally soluble, is 
rendered insoluble by the action of light, and which, in its insoluble 
state, resists the action of acids. Two substances of this character 
have been found which answer the purpose sufficiently well. The first 
is mineral pitch, asphaltum, or bitume de Judee, as it is called by the 
French ; and the second, gum, gelatine, or a mixture of both, to which 
has been added a certain proportion of the bichromate of potassa. 
The first of these materials was early employed in experiments on heli- 
ography by the elder Mepce, and it has since been very effectually used 
by Mepce de St. Victor and Mr. Charles Negre. Mr. Negre employs 
plates of steel, and after the first application of the mordant, covers the 
salient parts with gold, as in the process of Mr. Fizeau, above described. 
30 I A 



466 PARIS UNIVERSAL EXPOSITION. 

The use of the gelatine-bichromate was first suggested by Mr. Fox 
Talbot, the originator of photography upon paper, early in 1852. It is 
the basis of the processes now in most general and most successful use. 
Among those whose prints, obtained in this way, have been most 
admired, may be mentioned Messrs. Gamier, Placet, Pretsch, and 
Baldus, all of whom were exhibitors in the Exposition. Mr. Gamier 
presented a photographic view of the chateau of Chenonceaux side by 
side with a heliographic print taken from the same photograph, and 
with the plate from which it was printed. It would be difficult, without 
close examination, to distinguish the print from the original. Mr. Placet 
exhibited specimens of heliographic portraits which were distinguished 
for their remarkable beauty and finish. It is especially in this branch 
of the art that hitherto the greatest difficulties in heliographic engrav- 
ing have been met with. Mr. Garnier's plates are executed upon copper, 
which he protects by coating them electrically with iron. For this im- 
provement, applicable also, as elsewhere stated, to the hardening of the 
surfaces of ordinary types, and for the high degree of practical perfec- 
tion to which he has brought the art of heliography, Mr. Gamier was 
rewarded with the signal distinction of a grand prix. 

Another and simpler process by which very fine results are produced, 
was illustrated in the prints exposed by Messrs. Tessie de Motay and 
Marechal. In this process, the gelatinous coating of the plate is hard- 
ened by heat before exposure. It acquires thus a firmness sufficient to 
bear the pressure necessary to print from it directly. By soaking it in 
water after it has received the impress of the image, the parts of the 
coating unaffected by light swell up, while the others remain unchanged. 
These last take the ink from the roller, but the softened portions, being 
full of water, repel it. It follows that the photographic impressions 
must be made upon the plate by a negative. Plates prepared in this 
way are not very durable, a single one furnishing upon an average not 
more than seventy-five good impressions. On the other hand, the 
simplicity of the process of preparation permits their indefinite multi- 
plication. 

PHOTO-LITHOGRAPHY. 

The process just described can hardly be called heliography. It is 
analogous rather to what is called photo-lithography. This process is 
founded on the property already mentioned, of thebichromatized gelatine. 
and dates back as far as to the year 1855, when it was patented by Mr. 
Poitevin. As a means of copying line drawings and engravings, or 
printed or written documents, or maps, or charts, or any other devices 
which present no half tints, this art has become firmly established in 
industry, and has acquired a very sensible importance. The manner of 
preparing the stones for impression differs with different operators. 
By some, the sensitive coating is applied to the stone directly: br- 
others, a proof, first obtained upon paper, is afterward transferred to 



PHOTO-LITHOGRAPHY PHOTOGRAPH ENAMELS. 467 

the stone in the manner familiar to lithographers in the ordinary prac- 
tice of their art. 

PHOTOGRAPH ENAMELS. 

As naturally connected with the subject of heliography, a word may 
here be added in regard to the process, now so successfully pursued, 
and of which the results are so pleasing, and even brilliant, of trans- 
forming photographic plates into euamels, preserving all their original 
delicacy and beauty, and enriched by the addition of the most varied 
colors. Two methods are employed in the production of these colors. 
In the first, introduced and applied with remarkable success by Mr. de 
Camarsac, of Paris, colored vitrifiable powders are applied with the 
pencil to the different parts of the proof on glass, and the whole is 
raised to the necessary heat in a muffle. In the second, that of Messrs. 
Tessie de Motay and Marechal, of Metz, the photographic proof, taken 
in the ordinary way, but made as forcible as possible, is immersed in 
solutions of other metals by which the silver is displaced. If this be 
done successively in several baths, with exposure of different parts of 
the device in each, the subsequent process of enamelling will furnish 
corresponding varieties of tint. Some of the transparent enamels 
exhibited were of very large dimensions, a single subject being sufficient 
to fill an entire window. As compared with any of the stained-glass 
designs seen in the windows of churches and cathedrals, their vastly 
superior delicacy and beauty is obvious at a glance. 



THE EXACT SCIENCES. 



CHAPTER XV. 

GENERAL VIEW OF THE EXPOSITION IN CLASS 

TWELVE. 

Countries chiefly represented in this Class — The French section — Forms of 
apparatus which are new — the american section— model balances of the 
United States— Barlow's planetarium — Bond's astronomical clock and 

CHRONOGRAPH— TOLLES'S MICROSCOPE OBJECTIVES— WALES'S— TILLMAN'S TONOME- 
TER— HIS NEW CHEMICAL NOMENCLATURE. 

COUNTRIES CHIEFLY REPRESENTED. 

In the department embracing " instruments of precision and appara- 
tus for instruction in science, " the display presented by the Exposition, 
especially in the French and British sections, was very brilliant. The 
same was true, though less strikingly so, in the Prussian, Austrian, 
Belgian, Bavarian, Swiss, and Italian sections, and Russia also pre- 
sented some instruments of great interest. The French exposition of 
this class of objects was truly magnificent, embracing probably a richer 
collection than any of its kind that was ever before brought together. 
Taken as a whole, it formed a happy illustration of the existing condi- 
tion of experimental science, and exemplified strikingly the degree to 
which the recent progress of scientific discovery has been due to the 
achievements of art. 

Splendid, however, and interesting as was this remarkable display, it 
contained few things with which the scientific world were not already 
familiar. Many instruments appeared under improved models ; increased 
attention appeared to have been paid to the important object of com- 
bining the desirable qualities of lightness, strength, and rigidity ; higher 
precision of indications had evidently been successfully sought ; and 
examples of superior workmanship abounded on every side. Of appara- 
tus designed to be auxiliary to investigation, there were specimens which 
might justly be called miracles of skill. Of instruments intended only 
for illustration or for demonstration there were others constructed upon a 
scale of dimensions truly grand. But of instruments or apparatus new in 
principle, or designed to conduct into novel fields of inquiry, the Exposi- 
tion of 1867 was very nearly devoid. In static electricity, appeared here at 
a public Exposition for the first time the induction machine of Holtz ; 
and in dynamic electricity, the somewhat analogous machine of Ladd. In 
acoustics, the visible resolution of complex sounds by means of tremulous 



470 PARIS UNIVERSAL EXPOSITION. 

flames and revolving mirrors, which had not been exhibited in 1862, was 
first publicly presented. The application of the diapason to the meas- 
urement of minute intervals of time, for experiments in ballistics or in 
the experimental investigation of the laws of falling bodies, was also 
among the interesting things displayed in the Exposition of 1867, which 
had not been seen upon any former occasion of the same kind. But 
these and other similar evidences of progress in science, and improve- 
ments in the instrumental aids to observation or investigation, which 
figured prominently here, had become, for the most part, very generally 
known among men of science before the opening of the Exposition. 

The notices which follow relate mainly to this class of objects. It 
would be unprofitable, and for the purposes of a report like the present, 
unsuitable, to attempt a description in detail of the apparatus exhib- 
ited, since, except for the peculiarities of secondary importance which 
distinguish one instrument from another of its kind, this would be but 
to re- write the known history of science. The space devoted to this 
branch of the present report will therefore be brief. 

THE EXPOSITION OF THE UNITED STATES LN" CLASS 

TWELVE. 

It was impossible not to feel some regret in observing how imperfectly 
our own country was represented at the Exposition in this important 
department. We have not, it is true, a very numerous class of con- 
structors of instruments of precision, and there has been little demand 
as yet amoug us for the highest grade of artistic skill in the construc- 
tion of such instruments ; but we have some establishments, which, if 
they had put forth their strength, might have enabled us to present a 
display which, even in presence of the highest achievements of Euro- 
pean skill, could not have failed to do us honor. Americans asked, 
where are Ritchie, Green, McAllister, Wiirdemann, Zentmayer, Gru- 
now, Chamberlain, Pike % Our countrymen could not but feel that, while 
we were nowhere adequately represented, in this department our repre- 
sentation was so disproportionately inadequate as to be likely to pro- 
duce very unjust impressions abroad in regard to the state of science 
among us. Some things in the American department were, neverthe- 
less, very creditable. The very superior balances sent by the office of 
weights and measures under the Coast Survey at Washington, attracted 
much attention. The impression produced by them upon the superin- 
tendent of the bureau of weights and measures of the Russian empire, 
who was one of the imperial commissioners at the Exposition, was so 
favorable, that he made a formal proposition to purchase the whole set 
for his government. They were not, of course, for sale : but a state- 
ment transmitted to Washington as to his wishes, resulted, it is 
believed, in securing the transmission to the government of Russia of 
a complete collection of the model weights and measures of the United 
States. 



OBJECTS FROM THE UNITED STATES. 471 

BARLOW'S PLANETARIUM. 

The planetarium of Mr. Barlow, of Kentucky, was one of the attrac- 
tions of the American section in this class. The beauty of the appara- 
tus, the magnitude of the scale on which it is constructed, the ingenuity 
of its mechanism, the smoothness of the movements of its parts, and 
the variety of the phenomena which it illustrates, combined to secure 
for it universal admiration, and to keep it continually surrounded by 
curious groups. 

BOND'S ASTRONOMICAL CLOCK AND CHRONOGRAPH. 

The astronomical clock and chronograph of Bond were objects of 
still higher interest, and were also the most conspicuous among the 
objects in this class in the exposition of the United States, to which 
the term " instruments of precision" could be properly applied. They 
furnished one visible evidence, at least, to which we could point in proof 
of the existence among us of a very high order of mechanical skill. 

TOLLES'S MICROSCOPE OBJECTIVES. 

The objectives for microscopes, exhibited by Tolles, of Boston, and 
Wales, of New York, were, without doubt, equal to the best of their 
kind exhibited from any other country. It was to be regretted that 
these exhibitors did not accompany their glasses with the usual auxil- 
iary apparatus, and especially with stands permitting the glasses to be 
tested; both because of the more satisfactory trials which they could 
thus have secured, and because of the beauty of the display which a 
properly arranged optical apparatus presents to the eye. Under the 
circumstances, there was some difficulty in getting these objectives 
properly before the jury; but their merits were ultimately recog- 
nized, and were very handsomely rewarded. 

TILLMAN'S TONOMETER. 

Among the contributions from our country which should have had a 
place in class twelve, were two by S. D. Tillman, esq., professor of 
technology in the American Institute, New York, which, by some unex- 
plained error, were assigned to class thirteen, devoted to geography, 
cosmography, maps and globes. One of these was a device for illustrat- 
ing visibly the theory of the musical scale and of musical tempera- 
ment. This contrivance is called by its author a tonometer. Exter- 
nally, it is a thin book of quarto form, having the general appearance 
of a geographical atlas, and to this fact the error of its classification 
was probably owing. This error prevented the notice of the object by 
the jury of either class. The jury of class thirteen passed it by, as not 
being within their province; and it did not come before the jury of class 
twelve at all. When it was at length discovered to have been neglected 
entirely, the juries had completed their labors, and had dispersed. 

Owing to this accident, it seems to be but justice to the exhibitor to 
give some brief account here of his meritorious inventions. As to the 



472 



PAEIS UNIVERSAL EXPOSITION. 



tonometer, before entering into a particular description of its construc- 
tion, it will be necessary to premise a few observations relative to the 
subject which it is designed to illustrate. 

Whatever may be the physiological causes which determine certain 
combinations of musical sounds to be more agreeable than others, the 
physical conditions which must exist in order to produce this effect are 
well known. Combinations of sounds are more pleasing in proportion as 
the vibrations which produce the separate notes are more frequently coin- 
cident in time. Next to the unison, which is only a reduplication of the 
same sound, the concord which is smoothest to the ear is that between 
the fundamental note, or tonic, and the octave ; in which the numbers of 
vibrations performed in a given time are to each other as two to one. 
Other chords are formed of gradually decreasing smoothness by contin- 
ual additions of a unit to each term of this ratio, so that the series of 
harmonic sounds within the octave will be expressed by the fractions — 

Unison. Octave. Fifth. Fourth. Major third. Minor third. 

1 2 3^ £ 5^ 6_ n 

1 1 O . Q A K. \ ' 



Beyond this point the series cannot be carried, the combination J pro- 
ducing an effect unpleasing to the ear, or discordant. 

The octave, its extremes excluded, embraces six notes. Intervals being 
named according to the number of notes of the diatonic scale which they 
embrace, including the extremes, the six notes form a series number- 
ing from the second to the seventh. The series of simple ratios given 
above furnishes three of these only — the third, fourth, and fifth ; the 
minor third above the tonic not being a diatonic interval. The sixth is 
implicitly given by the ratio f , since this note is a sixth below the octave 
but it is not necessary to deduce it in that manner. 

By advancing the tonic successively to the several points in the scale 
represented by the simple ratios above, preserving still the numerical 
relations with the original fundamental note, and establishing upon each 
such newly chosen tonic the successive concords represented by the frac- 
tions in the series (I), other intervals will be obtained which will supply 
the three remaining notes of the scale. Thus : 



1. 

2, 
3.. 



Tonic. Fifth. 

9 



X ^ = 



-~- x 



Tonic. 

3 

2 

Tonic 
^3 

2 



Ninth. Second. Tonic. 

9__ 4£ 9^ 

4 = 4 8 

Fourth. Octave. 

4_ _ 12 2 

3 "6 ~~ T 

Third. Seventh. Tonic 

8 
Tonic. Minor third. 

6.6 



X -r = 



4 

5. 

6. 



Minor third. 
I X t 



Tonic. 

4 x 



7. 






Flat seventh. 

IS _9^ 
5 10 = 5 

Third. Sixth. 

A = r? = A 
4 12 = 3 

Minor third. Minor sixth. 

6 24 . 8 

V A. -=r- =-= -=■ 

Dissonance. 

36 

25 



tillman's tonometer. 473 

The first of these derivatives is the interval of the second ; the third 
the interval of the seventh ; and the fifth the interval of the sixth. The 
diatonic scale is thus completed, and the places of its several notes are 
fixed by unalterable mathematical relations. Eeferred to the funda- 
mental, they are — 

Tonic. Second. Third. Fourth. Fifth. Sixth. Seventh. Eighth. 

1954 35152 (JJ \ 

184323 8 1 ( "' 

The last is the repetition of the tonic, and the notes above repeat 
those of the original scale, doubling, quadrupling, &c, the numbers of 
vibrations. When the numbers of vibrations corresponding to these 
several notes are compared, not with the number belonging to the tonic, 
but each with the number immediately preceding, the intervals between 
the successive notes will be found to be the following: 

Tonic. Maj. tone. Min. tone. Semitone. Maj. tone. Min. tone. Maj. tone. Semitone. 

1 9 10 16 9 10 9 16 , rm 

1 8 9 15 8 9 8 15 "" { ' } 

Eeduced to a common denominator these fractions become — 

Tonic. Maj. tone. Min. tone. Semitone. Maj. tone. Min. tone. Maj. tone. Semitone. 
360 405 400 384 405 400 405 384 (jy . 

360 360 360 360 360 360 360 360 "* '' 

The successive diatonic intervals are therefore of three different mag- 
nitudes, which are to each other as the numbers 45, 40, and 24 ; or as 9, 
8, and 5, nearly. These latter numbers are commonly taken to represent 
them, although the last is a little too large. In this series 9 is the major 
tone, 8 is the minor tone, and 5 the semitone. The unit is the difference 
between the major and minor tones, and is called a comma. Hence we 
have — 

For the entire octave, 9+8+5+9+8+9+5=53 commas. 

For the fifth, 9 + 8+5+9=31 commas. 

In point of fact, if the exact difference between the major and minor 
tones be taken as the unit, the number of commas in an octave, cor- 
rectly estimated, is more than fifty-five and a half; but for ordinary 
uses, the values above given, as they are most convenient, are also suf- 
ficiently correct. 

Since these inequalities exist between the successive intervals of a 
true diatonic scale, it follows that if the second or third, or any other note 
of the scale, be taken as the tonic note of a new scale, the notes of the 
new scale will not all of them correspond with those which follow in the 
same order in the primitive scale, and which approach nearest to them 
in pitch. This consideration, which is unimportant in the case of such 
musical instruments as admit of the indefinite variation of their tones, 
affects quite seriously the harmonies of one of which the scale is fixed 
and the number of notes of different pitch within the octave is lim- 
ited. And an examination of the following table will show that an 
instrument in which, as in the piano, this number is no greater than 
twelve, must in many of its keys be very imperfect. 



474 



PARIS UNIVERSAL EXPOSITION. 



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to E © a. 

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OS 






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fen 


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c3 


















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1 


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a 




2 






















■a 






- 


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d 




















C 

■x. 






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a 


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■ 


-z. 


oi 


!S 


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s 


E- 


x 


£ 


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— 


so 



TILLMAN'S TONOMETER. 475 

In order to avoid fractions, the number of vibrations of every note is 
referred to tliat of a fundamental tonic assumed at 5760 to the second, 
and only the keys corresponding to the natural notes of the diatonic 
scale are given. If the keys deduced from all the notes of the chromatic 
scale were added, the diversities would be much more numerous. The 
numbers included between the heavy lines passing diagonally through 
the table, are those of the complete octave in the successive scales. The 
other numbers are added for the purpose of comparison. It will be seen 
that in the key of D there are four notes which differ from those 
approximating the same pitch in the primitive scale, and that D has 
itself, in the different series, the three different values 6480, 6400, and 
6750. In the key of B, all the notes but two differ from those in the 
original key of C. 

If all the tones were equal, and if the semitone were half a tone, as its 
name implies, these discrepancies would not occur. The octave would 
consist of twelve equal semitones, and a twelve-keyed instrument would 
be equally perfect on every scale. In order to reduce the complication 
of instruments, the expedient naturally suggests itself to introduce such 
an equality, by altering the notes to some slight extent, so that while 
the instrument is quite perfect upon none of its scales, it shall be equally 
imperfect upon all. Such a temperament requires but five finger-keys 
to be added to the seven which form the diatonic octave, and makes 
each key interposed between every two full tones equally serviceable for 
the flat of the note above and the sharp of the note below. In point of 
fact such flats and sharps differ from each other by one or two commas, 
and the natural semitones never coincide with those of the chromatic 
scale. The temperament here proposed is not agreeable, and the method 
actually practiced is to modify the notes in such a manner as to keep 
nearest to the truth in the most frequently recurring scales. 

Another reason for the necessity of temperament of some sort arises 
out of the incommensurability of the simple numbers two and three, and 
their powers ; so that in passing through a series of fifths or fourths, in 
modulating from key to key, an exact transition is impossible. Taking 
the value of the octave at fifty-three commas, and that of the fifth at thirty- 
one commas, seven octaves will amount to three hundred and seventy- 
one commas, and twelve-fifths to three hundred and seventy -two com- 
mas ; whereas, if the fifth were seven-twelfths of the octave, as in equal 
temperament it would be, twelve-fifths should be precisely equal to 
seven octaves. If the exact difference between the major and minor 
tones, viz., f i, be taken as the value of the comma, the value of twelve- 
fifths will be 391.67, and that of seven octaves 390.58 ; the difference 
being 1.09, or about a comma and a tenth. 

Of all this subject, which is so little understood by most persons who 
make use of musical instruments, Prof. Tillman's Tonometer furnishes 
a simple elucidation, which, by directly addressing itself to the eye, con- 
veys the truths to be illustrated more directly and more clearly than 



476 



PARIS UNIVERSAL EXPOSITION. 



pages of numerical statements can do. A circle represents the octave, 
(the septate Prof. Tillman calls it, taking the name from the number of 
intervals rather than from the number of notes required to produce them.) 
This is divided into twelve equal semitones, or grades, as he names them, 



Fig. 94. 




Tillman's Tonometer Dial. 

each containing five artificial commas, making sixty in all. Seven white 
escutcheons mark the places of the notes of the natural diatonic scale ; 
and five black escutcheons indicate the interpolated semitones. Two 
circular musical staves connecting these escutcheons show the places of 
the several notes as written in the tenor and in the bass. The C, as the 
tonic note of the natural scale, takes its place at the top of the circle. 
The other letters follow in their order. But while the system of equal 
temperament is shown by the twelve visible grades, the proper places of 
the notes of the chromatic scales are shown on the circular division with 
proper marks. This is the fixed part of the apparatus. 

Within the circle just described is a movable circle revolving on the 
common center, and carrying seven conspicuous arms, each terminated 




tillman's tonometer dial. 477 

by a spearhead, which point to the several notes of the natural diatonic 
scale as determined by equal temperament, when the leading arm is 
brought opposite to the origin at C. If the same leading arm is brought 
opposite to any other letter or escutcheon, the remaining arms point 
out in like manner the notes of the corresponding scale, and indicate 
such as are affected by sharps or flats. Five less conspicuous arms, end- 
ing each in a star, divide equally the spaces which, in the first system, 
represent the full tones. 

So far, the instrument is useful in illustrating the construction of the 
different scales, and in teaching modulation. But the circumference of 
the revolving circle is divided into fifty- 
three commas instead of sixty, and it 
shows, by means of arrows directed to the 
proper divisions, the places of the true or 
untempered notes in every scale ; and ex- 
hibits therefore at a glance the degree to 
which the system of equal temperament "^ 
does violence to the natural relations of 
the notes to each other. And thus it fur- 
nishes the means of studying the effect of 
any temperament, and of easily comparing 
one system with another. As an aid to ^gfh?#" 

the musical education of such students as do not desire to be profound, 
its usefulness cannot but be very great ; since, with little effort on the 
part of the learner, it conveys definite ideas upon a subject respecting 
which very many form no clear notions at all. 

Prof. Tillman has an ingenious mode of representing pitch, and illus- 
trating the recurrence of musical sounds in a succession of octaves, by 
means of a spiral in which the radius vector is the index of the pitch, 
and a series of fixed radii mark the places of the notes in the diatonic 
scale in every octave. The law of this spiral will be expressed by the 
equation 

dr=ady, 

supposing r to be the radius vector, and <p the angle described from the 
origin. If r=l when ^=0°, and r=2 when <p =2tt, the value of a will 
be i. In order, then, to connect the length of the radius vector with 
the numbers of vibrations corresponding to its different positions and 
lengths, we must suppose the revolution to begin when r = l, and 
assume the initial number of vibrations per second = n. Put also the 
number at any subsequent point = N. Then the number of revolu- 
tions, integral or fractional, which may be put = v will be = r — 1. 

And v = r — 1 =~. Also N = n2v = n2r\ 

Whence : Log X = Log n + (r — 1) log 2. 

And r = Log N ~ log n + log 2 ' 
log 2 



478 PARIS UNIVERSAL EXPOSITION. 

If we put K= 6502, and n= 512, we shall obtain r = 4.67 = 4§. And 
v=r— 1=3.67, showing that the radius belongs to the fourth turn of 
the spiral at 240° from the origin. 

Prof. Tillman's tonometer is accompanied by a concise treatise on the 
general principles of music, including harmony and modulation, which 
this instrument serves very happily to illustrate. 

TILLMAN'S PROPOSED CHEMICAL NOMENCLATURE. 

The other part of the contribution of Prof. Tillman to the Exposi- 
tion consisted in a project for a new chemical nomenclature, designed 
to remove the disadvantages attending the existing cumbrous system, 
which, with the progress of the science, especially in the organic 
department, is becoming daily more embarrassing. While it is pecul- 
iarly adapted to the typical mode of classification which is continually 
gaining ground and is likely to become universal, it accommodates itself 
equally to the older form, and is suited to be of the greatest utility, 
considered merely as a system of mnemonics, to those who prefer to 
use it simply as an auxiliary to forms with which they are already 
familiar. The advantages of the scheme are briefly — 

1. It provides for every known or possible combination a distinct 
significant name, expressing briefly, and usually in a single word, all 
the elements which enter into the compound, with the proportions in 
which they enter. 

2. It enables any one to give at once to any new or supposed com- 
pound, a name which shall be immediately intelligible to every othe\ 
person ; and makes it equally possible also to understand the nature o\ 
any compound named by another. 

3. It simplifies exceedingly the machinery of thought, assisting the 
chemist in this respect very much as the mathematician is aided by the 
symbols of algebra and arithmetic. 

The principles according to which this nomenclature is constructed, 
are concisely stated by the author as follows : 

" 1. The system is based on abbreviations of the universally received 
names of the metals, and on the chemical symbols of the metalloids or 
non-metallic elements, with such modifications as were imperatively 
required. 

"2. The name of each chemical element relates, not to its mass, but 
only to a minimum combining proportion termed an atom, or to some 
multiple of it. The atom is therefore the unit of measurement, and the 
starting point of the scale in each series of compounds. 

" 3. The atomic name of each metal consists of two syllables, and 
ends with the consonant m. 

u t. The name of each of the thirteen metalloids terminates with a 
different consonant. Arsenic and tellurium, classed by French chemists 
among the metalloids, have in this arrangement the terminal letter com- 
mon to the metals. 



tillman's proposed chemical nomenclature. 479 



" 5. The number of atoms of any element is designated by the vowel 
immediately preceding its terminal consonant. The numerical power of 
the vowels advances with the order in which they are placed in the 
alphabet. One, two, three, four, and five are respectively expressed by 
a, e, i, o and u, having the short or stopped sound as heard in bat, bet, 
bit, hot, hut ; and six, seven, eight, nine and ten by the same vowels hav- 
ing a long or full sound. In foreign languages, it may be best to desig- 
nate the long sound by a sign placed over the vowel; but in our lan- 
guage, it is found by experience more convenient to place e before each of 
the vowels, which invariably indicates their long or full sound as heard 
in the words great, greet, sleight, yeoman, euphony. These ten distinctive 
sounds may be illustrated by a single example. From one to ten atoms 
of iron, inclusive, have the following names : 

Fe, Ferram ; Fe 2 , Ferrem ; Fe 3 , Ferrim ; Fe±, Ferrom ; Fe 5 , Ferrum ; Fe 6 , 
Ferream ; Fe 7 , Ferreem : Fe s , Ferreim ; Fe 9 , Ferreom ; Fe^, Ferreum. 

The proper diphthongs are sometimes used for the even numbers between 
10 and 20. These will be remembered from the fact that their value is the 
sum of their vowel- values, either short or long : thus, oi is 12 = 9 + 3 ; 
on is 14 s= 9 + 5 ; an is 16 = 6 + 10 ; oo is 18 = 9 + 9. The consonant y 
is 10, and used only in connection with vowels, which will express all 
the numbers to and including 20 ; w is 20, and, with the usual append- 
ages, will express the numbers to and including 30. X is also used, and 
when preceded by a vowel, which thus has the power of an exponent? 
will express a progression by tens to one hundred ; thus 10, ax ; 20, ex ; 
30, ix ; 40, ox; 50, ux; 60, eax; 10,eex; 80, eix; 90, eox; 100, eux. In 
the same manner these vowels preceding qu express the hundreds to and 
including one thousand, and the intermediate numbers are represented 
by suffixing some of the characters previously explained. 

« Very few chemical compounds, now known, have a composition rep- 
resented by atomic numbers higher than one hundred. A large majori- 
ty of the bodies of known composition do not require numbers as high 
as ten. The following selections will show more clearly the numerical 
value of each letter, and the extent to which this numerative system may 
be carried: 



1 


ea, 6 


aa, 11 


y, io 


w, 20 


2 


ee, 7 


oi, 12 


ya, i 


wi, 23 


3 


ei, 8 


ou, 14 


yi, 13 


wee, 27 


4 


eo, 9 


au, 16 


yeo, 19 


weo, 29 


5 


eu, 10 


oo, 18 


yen, 20 


weu, 30 



ax, 


10 


aqu, 100 


ex, 


20 


equ, 200 


ix, 


30 


eiqii, 800 


eix, 


80 


eoquix, 930 


eux, 


100 


euqueix, 1080 



" 6. The following metalloids have names terminating with their well- 
known symbolic letters -, one atom of each is here denoted : 



Fluorine, 

Nitrogen, 1 

Carbon, 



fluraf or af; 
nitran or an; 
carbac or ac : 



Bromine, bromab or ab ; 
Phosphorus, phosap or ap ; 
Sulphur, sulphas or as. 



1 In the French, Azan. 



480 PARIS UNIVERSAL EXPOSITION. 

" Iii a few instances where the symbolic letter could not be used, the 
terminal letter adopted may be associated with some prominent charac- 
teristic of the element. Thus I represents the lightest of substance, an 
atom of hydrogen is hydral or at ; d represents the densest of the gaseous 
elements, an atom of chlorine is chlorad or ad ; v represents a volatile 
producing a violet vapor, one atom of iodine is idav or av. The atom par 
excellence is at ; oxygen, exceeding in quantity all other elements of the 
earth's crust, has for the name of a single atom oxat or at. An atom of 
selenium is selaz or az ; it bears a strong resemblance in its reactions to 
as. Boron and silicon or silicium, like carbon, are permanent solids 
when isolated $ their terminals may be remembered by the association 
of j and Tc in the alphabet ; an atom or boron is bo raj or aj, an atom of 
silicon is silak or dk. 

" The compounds of carbon and hydrogen are so numerous that it has 
been found essential to provide an additional character to represent 
each. The letter r may be associated with the radiating and refracting 
power of carbon • and carbar or ar, as well as ac, will represent an atom 
of carbon. As ac might be mistaken for aJc, in radical compounds, the 
carbon component is denoted generally by r. 

" The only case in which it has been found advantageous to use one 
letter to designate two atoms, is that of li for two atoms of hydrogen, or 
liydrel ; thus preserving the ratio of the old combining numbers, C 2 H 2 2 
being cht. It will be noted that acli corresponds with C 2 H 2 in the old 
notation, and with CH 2 in the new : it is the key to a series of radicals, 
i. e., methyl, CH 3 , is achat; ethyl, C 2 H 5 , echal. 

" 7. Metalloid terminal syllables express as much as the full name, 
and are used as suffixes to names of metallic atoms to denote a metallic 
compound 5 for example, the protoxide of iron is ferramat, which indi- 
cates very clearly that one atom of iron is united with one atom of oxy- 
gen. A combination of metalloid syllables represents a non-metallic 
compound. In numerous cases, the number of syllables forming such a 
word is less than the number of different elements in the compound, 
because two or more terminal characters may be united, and the vowel 
or diphthong preceding the whole will be applicable to each ; for instance, 
elt = H 2 2 is a molecule of oxygenated water, or peroxide of hydrogen ; 
am = CN is an atom 1 of cyanogen, and ant =XO is a molecule of binoxide 
of nitrogen. It will be seen presently that the names of salts containing 
one atom of a metal are sometimes slightly abbreviated, by omitting the 
a which should precede m; also that m, with a vowel preceding it. is 
applied to multiples of any radical playing the part of a metal." 

These principles are applied in an essay extending to twenty or thirty 
pages, in which the application is pursued into every branch of the sub- 
ject, and the adaptability of the system to every variety of theoretic 
view is illustrated by examples. The following instances serve to show 
the extent to which it carries abbreviation in some of the compounds 
produced by substitution in organic chemistry : 

1 Atoinoid ? 



tillman's pkoposed chemical nomenclature. 481 



Chlorides and bromides of naphthaline, ivith Gmelin's names and formula?. 



Gmelin's names. 


Gmelin's formulae. 


New names. 




C 10 H 6 BrClHCl 

Ci H4Br 4 HBr 

CioH 6 Cl 2 2HCl 

CjoHeBrCl 2 HCl . . . 
CioH 4 Br 2 Cl 2 2HCl.. 
Ci H 4 Br 2 Cl 2 2HBr.. 
Ci H 4 Br 3 C12HBr... 
Ci H 4 Br 4 2HBr .... 
C 10 H 3 Br 2 Cl3 2HCl.. 
















Bihydrochlorate of bibromobichloronaphthaline 

Bihydrobromate of bibromobichloronaphthaline — 

Bihydrobromate of terbromochloronaphth aline 

Bihydrobromate of quadribromonaphthaline 

Bihydrochlorate of bibromoterchloronaphthaline 


= eurealebod. 
= eurealedob. 
= eurealadub. 
= eurealb. 
= eurulebod. 



This nomenclature would be worthy of attention, if it were only on 
account of the remarkable abbreviation which it introduces into the lan- 
guage of the science; but the author claims for it, justly, a greater 
advantage in the fact of its comprehensive signiiicancy. This idea is 
expressed in the remark that a he who knows why he calls chloroform 
arlidj knows on the instant, and knows for life, that it is composed of one 
of carbon, one of hydrogen, and three atoms of chlorine ; or when he 
designates laughing gas by genat, he announces at once several facts not 
indicated by the old names, nitrous oxide or protoxide of nitrogen." 
31 I A 



CHAPTEE XVI. 

PHYSICS. 

Gravity— Densimeters— Balances— Laws of gravity— Pneumatics— Geissler's 
air-pump without valves — kravogl's mercurial air-pump— rlcharl/s mul- 
TIPLE exhaustion — Deleuil's— Sound— Kcenig's exposition — Sirens — Resona- 
tors — Scheibler's tonometer — Graphic methods in acoustics — Optical 
methods— Mechanical and optical methods combined— Sonorous flames — 
Heat— Thermometers— Pyrometers— Light— Optical glass — Topler's strle 
detector— Polarization apparatus— Phosphorescence— spectroscopes— Euth- 
erfurd's solar spectrum — telescopes— microscopes — static electricity— 
Electro-static induction machines— Varley's— Topler's — Holtz's— Bertsch's 
—Dynamic electricity — Batteries— Ebner's— Farmer's— Secchi's— Callaud's 
— Minotto's — Marie-Davy's — Leclanche's — Bunsen's bichromate battery— 
Thomsen's polarization battery — Thermo-electric batteries — Farmer's— 
Marcus's— Becquerel's — Electro-magnets— Induction coils— Geissler's tubes 
— De la Rive's aurora apparatus — Meteorology— Automatic meteorological 
registers — Secchi's meteorograph. 

L_GKAYITY. 

Instruments which are employed to determine the densities of liquids, 
the weight of masses of matter in any form, the absolute force of gravity 
at different elevations or in different latitudes, or finally, the laws which 
govern the motion of bodies falling freely under the influence of gravity, 
or acted upon by gravity jointly with other forces, including their own 
inertia, may all be properly considered under the general title placed 
at the head of this section. 

DENSIMETERS. 

The nomenclature of instruments designed to ascertain densities by 
direct observation has been quite unnecessarily extended. Besides the 
terms hydrometer, areometer, and volumeter, which are generally familiar 
and have relation to the physical properties of matter in the liquid state, 
we have also, aleoometers, laetimeters, saccharimeters. alkali meters, and 
many others, denoting the special objects for which the instruments so 
named are intended. It is greatly to be desired that this confusion of 
terms and consequent multiplication of the forms of an instrument 
which, under all its varieties, fulfills only one and the same function 
always, viz : that of determining the specific gravity of a liquid in which 
it is plunged, should be done away with. A densimeter does not indi- 



DENSIMETERS. 483 

cate the quantity or proportion of alcohol, or sugar, or alkali, in a solu- 
tion. It indicates only the weight of a unit of bulk of the solution as 
compared with that of an equal bulk of water. The proportion of alco- 
hol, salt, &c, which corresponds to this specific gravity, may be found 
from tables in which have been arranged the results of carefully con- 
ducted experiments on mixtures. With the help of such tables, the 
same densimeter may be used for all the varieties of purpose for which 
many constructors now provide independent instruments. There could 
of course be no objection to providing a densimeter with a double scale, 
having one graduation for general densimetrical purposes, and another 
for alcoometry, saccharimetry, &c, as the case may be ; but the second 
scale, without the first, limits the use of the instrument to one special 
object. Hence, it was one of the recommendations of the international 
congress assembled in Paris, during the continuance of the Exposition, 
to deliberate on the unification of weights, measures, and coins, that all 
densimeters should hereafter be constructed to indicate specific grav- 
ities, as referred to water taken at its maximum density. 

Among the densimeters on exhibition in the Exposition, there were 
noticed no noA^elties of special interest. These instruments were for the 
most part constructed of glass ; but in the Russian section Mr. L. 
Andree, of Riga, presented some elegantly finished models in aluminium 
bronze. The material of which a densimeter should be constructed, is a 
question upon which opinions are divided. It is objected to metal, that 
its malleability and flexibility make it liable to change of form by acci- 
dent or by fraudulent design. But such are the extreme hardness and 
rigidity of aluminium bronze, that the objection here suggested, so far 
as this metal is concerned, is rather more imaginary than real. It is, 
however, a more serious objection that the size of a densimeter of metal 
may be skillfully reduced by a file or scraper, the injured parts being 
subsequently repolished, or gilded over in case the instrument had been 
originally gilded. Against the possibility of this description of fraud, 
however, is to be offset the absolutely certain detection which follows, 
when the instrument is carefully weighed in the air. Glass, on the other 
hand, cannot change its figure by percussion or compression, nor can it 
be reduced in size by abrasion without the destruction of a polish which 
cannot be easily renewed. The bulb of a glass hydrometer might be 
varied in size under the glass-blower's blow-pipe ; but supposing it to 
have been originally silvered on the interior, or coated with any varnish 
permanent at ordinary temperatures, this kind of fraud could not be 
successfully practiced. But the fragility of glass hydrometers is a great 
disadvantage, and in the public service is the occasion of frequent incon- 
venience. Horn-rubber, or ebonite, would seem to combine the quali- 
ties most desirable in an instrument of this description. This material 
has been proposed by the present reporter, and perhaps by others, for 
the uses of the United States revenue service ; but for reasons not fully 
understood, or so far as understood by no means satisfactory, construe- 



484 PARIS UNIVERSAL EXPOSITION. 

tors have been unwilling to adopt it. The belief is, nevertheless, confi- 
dently entertained that this material will ultimately be found, for ordi- 
nary densimetric purposes, preferable to any other. 

BALANCES. 

The balances shown in the Exposition, which were numerous and in 
many instances elegant, were distinguished rather for excellence of 
workmanship, and for the delicacy of their indications, than for origin- 
ality in regard to construction. In this latter respect, the only real 
novelty noticeable consisted in the " arc of precision " invented a few 
years since by Gallois, and recently adopted by some of the best known 
constructors of France, Belgium, and Germany. This is an expedient 
for making delicate determinations of fractional weights, by deflecting 
more or less to the right or left an index needle attached to the beam of 
the balance beneath the center of gravity. When this index points 
directly downward, like the ordinary fixed needle of the balance, its 
effect upon the equilibrium of the balance is of course zero. When 
deflected so as to form an oblique angle with the horizontal axis of the 
beam, it contributes a portion of its weight, dependent on the amount of 
deflection, to the side toward which it is inclined. When, in the pro- 
cess of weighing, a position of the needle has been found which pro- 
duces equilibrium, the fractional weight contributed by the needle is 
read upon a circular arc, which is situated immediately behind it, and is 
suitably divided. The division, of course, must be made experiment- 
ally at the time of the construction of the balance. 

Hitherto the most popular expedient for ascertaining these slight 
differences has been the divided scale beam and the riding weight. 
The riding weight is a twisted wire of platinum or gold, hardly larger 
in diameter than a hair, which is picked up and transported from point 
to point on the balance beam, by means of a sliding-rod passing through 
the side of the case and operated from without. This contrivance is 
less simple than that of Gallois, and requires some dexterity to man- 
age it well. Which of the two affords practically the best results 
remains to be settled by experience. 

Very fine balances, furnished with the arc of precision, were exhibited 
by Messrs. Sacre, of Brussels, J. and L. Beiman, of Berlin, and Heinpel 
and Collot, of Paris, who also presented balances of the ordinary con- 
struction. 

The sensibility of the balances exhibited may be judged of from the 
following examples, in which the load in each scale is expressed in grams 
and the turning weight in milligrams, or fractions of a milligram : 



SENSIBILITY OF BALANCES. 



485 



Constructor. 



Load in 


Turning 


each scale. 


weight. 


30 


0.05 


100 


0.2 


100 


,0.1 


100 


0.1 


250 


0.5 


500 


0.2 


1,000 


1.0 


1,000 


0.1 


1,000 


0.5 


1,000 


0.2 


2,000 


0.5 


2,000 


1.0 


5,000 


0.5 


5,000 


5.0 


5, COO 


0.5 


20, 000 


1.0 


35, 000 


5.0 



Ratio turning 
weight to load. 



Hempel, Paris 

Hagershoff, Leipzig... 

Sauter, Elbingen 

Kravogl, Innsbruck . . 

Collot, Paris 

L. Reiman, Berlin 

J. Reiman, Berlin 

Horn, Berlin 

Rohrbeck, Berlin 

Saxton, United States. 

Hempel, Paris 

Collot, Paris 

Sacre, Brussels 

Hagershoff, Leipzig . . 

Deleuil, Paris 

Saxton, United States. 
Collot, Paris 



1 

1; 
1:1, 
1:1, 
1; 
1:2, 
1:1, 

1:10, 
1:2, 
1:5, 
1:4, 
1:2, 

1:10, 
i:L, 

1:10, 

1:20, 
1:7, 



:600, 000 
500, 000 
000, 000 
000, 000 
500, 000 
500, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 
000, 000 



The large balance of Collot was the most remarkable object of its 
Mud exhibited by any European constructor. The beam was of fifteen 
kilograms weight, and rested on knife-edges of steel supported by plane 
surfaces of agate. The long index needle was constructed of alumin- 
ium, in order to diminish its weight, and the whole apparatus was sus- 
tained upon a base of cast iron, which, for the purpose of securing sta- 
bility and neutralizing tremors, was made of the great weight of nine 
hundred kilograms, (nearly a ton.) This balance being intended for the 
verification of the larger measures of capacity, is provided with auxil- 
iary apparatus to facilitate loading and unloading. A small car, run- 
ning on a railway, receives the charge and conveys it up to the scale, 
when, by means of a kind of derrick, it is transferred to the platform 
without shock or jar, and without requiring the operator to touch it 
with his hand. 

The large balance exhibited by the Bureau of Weights and Measures 
of the United States Treasury Department, also attracted much notice 
from its simplicity, strength, judicious proportions, and excellent work- 
manship. The smaller balances exhibited along with this were also 
much admired. By some accident these balances did not appear in the 
catalogue of the Exposition. They were, therefore, overlooked by the 
jury of the class to which they belonged ; a circumstance of less import- 
ance, as they would probably have been pronounced Jwrs concours. In 
the year 1851, balances identical in construction with those exhibited in 
1867 were presented by the government of the United States to that of 
France, as a part of a set of the standard weights and measures of our 
country, sent in exchange for a similar set of the French weights and 
measures previously received. The judgment of Mr. J. C. Silbermann, 
at that time superintendent of the collections of the Conservatoire des 
Arts et Metiers, and then the highest authority in France in this branch 



486 PARIS UNIVERSAL EXPOSITION. 

of applied science, in regard to the merit of these balances, was expressed 
in a letter to Mr. Alexander Yattemare, agent of international exchanges, 
under date of March 6, 1852, and was so emphatic and so complimentary 
that the reporter may be pardoned for reproducing it here. Mr. Silber- 
mann says : 

" In the first place I will communicate to yon the opinion of connois- 
seurs, and I beg of yon to believe that each instrument has been well ex- 
amined and well appreciated. This opinion is, that all these articles are 
of irreproachable execution ; the two balances particularly are the objects 
of universal admiration. Public opinion cannot go further. In testimony 
of the esteem in which I hold these balances, I cannot say more than 
that I used the small one to adjust the platinum kilogram, which was 
exhibited at the World's Fair, in London ; it is very delicate and especially 
most constant. I was able to make all my weighings with certainty 
to within half a milligram. The form adopted for these balances is 
at once simple, well adapted to use, and distinguished by that taste 
which is only to be found in instruments made by master hands. These 
are justly to be termed instruments of precision. 

" What I have just said with regard to the small balance, I may repeat 
with still more propriety respecting the large one : it is not inferior to 
the former in precision. In fact I have tested it with ten kilograms in each 
scale, and it promptly indicates a difference of one-half a milligram 
between the two weights; that is to say, one unit in twenty millions in 
each scale. I have been obliged several times to repeat this experiment 
in presence of incredulous persons, and it has always given the same 
result. What is most gratifying to me in the construction of these 
balances, is the system adopted in the United States, which consists in 
preventing the oscillation of the balance, and causing it to tilt as soon 
as the equilibrium is destroyed; the weighings are effected very rapid- 
ly, and, as it has been seen, with as much precision as can be obtained 
with the most carefully made balances. For my part, I have ever re- 
gretted that all our balance-makers have hitherto declined the adoption 
of this system. They assign, as the reason of this reluctance, that. 
with an oscillating balance, they can replace the small weights by arcs 
of oscillation, which enables them to estimate much smaller fractions of 
the milligram. As for myself, I am inclined to believe that as much 
precision may be arrived at in one system as in the other: and in That 
case there will be a great gain of time in the system of tilting. More- 
over, I know from experience what confidence is to be placed in weights 
estimated by arcs ; in spite of the utmost care, the above-mentioned 
very small arcs are variable ; and, while they flatter us with the hope 
that we have obtained tenths of a milligram, they cause us to commit, 
unwittingly ? errors of more than one or two milligrams." 

The good opinion of these balances thus expressed fifteen years ago 
by Mr. Silbermann continues to be entertained of them by his able and 
efficient successor, Mr. Tresca. This gentleman, on whom it devolves 



BALANCES ACCELERATION OF FALLING BODIES. 487 

to make all the comparisons of standard weights and measures furnished 
by the imperial government to the provinces or to foreign countries, 
stated to the present reporter that in the comparison of heavy weights 
he always used the large American balance in preference to any other. 

Before leaving the subject of balances, mention should be made of 
the alarm balances, or automatic hammer balances, as they are called 
by the exhibitor, Mr. Deleuil, which appeared in the French section. 
One of the forms of the instrument so named was originally constructed 
for the municipal service of Paris, to be employed in testing the illumi- 
nating power of the gas furnished for lighting the streets. The stand- 
ard light employed in the process of testing is an oil lamp regulated 
to a uniform consumption. The gas is burned in a porcelain burner. 
As for the photometer, its construction is quite simple. In the metal 
base of a hollow cone are introduced two disks of ground glass, on one 
of which falls the light of the lanip, and on the other that of the gas 
jet. The experiment is conducted, as a matter of course, in a dark room ; 
and the observer placing his eye at the truncated summit of the cone, 
causes the flow of gas to be regulated until the two disks appear of 
equal brightness. The lamp is accurately equipoised upon the scale of 
the alarm balance, and then a certain number of grams is removed from 
the counterbalancing scale. As the oil is consumed the lamp gradually 
loses weight, till at length the scale beam tilts in the opposite direction. 
This tilting causes the fall of a light hammer which is attached in a ver- 
tical position, with the hammer head uppermost, to the index needle of 
the balance, and which is prevented by a stop from falling toward the 
lamp, though it is free to fall in the opposite direction so soon as the 
needle passes the vertical. The hammer falling upon a bell gives notice 
to cut off the gas. Then by a comparison of the consumption of gas 
indicated by the meter with the known weight of oil consumed, the 
inference as to the quality of the gas is easily deduced. 

The same principle has been applied by Mr. Deleuil to the determina- 
tion of the exact amount of gold or silver deposited in the process of 
galvanic plating and gilding. In this case the objects receiving the 
deposit determine the tilting of the balance when their weight has been 
increased by the amount desired; and as this point may be reached in 
the absence of attendance, the movement is made to arrest the operation 
by breaking the electric circuit. 

LAWS OF GRAVITY — ACCELERATION OF FALLING BODIES. 

The velocities acquired by bodies falling freely under the influence of 
gravity are so great as to render the investigation of the law of accel- 
eration by direct observation extremely difficult. On the one hand, if 
the spaces fallen through are small, the duration of the experiment is 
too brief to furnish satisfactory results. The minutest error in assign- 
ing the exact instant of commencement or end of the fall will seriously 
affect the value of the observation. On the other hand it is difficult to 



488 PARIS UNIVERSAL EXPOSITION. 

find situations in which bodies can be observed in their descent from 
great heights; and even supposing this difficulty less, the observations 
on such falls would be vitiated and rendered practically useless by the 
great resistance opposed by the atmosphere to all bodies moving with 
high velocities. 

The most satisfactory instrumental means of visibly illustrating 
the laws of falling bodies has hitherto been found in the machine 
invented about a century ago by George Atwood, which is familiarly 
known in every physical lecture-room under the name of At wood's 
machine. In this machine, a light wheel, delicately supported upon 
large friction wheels, carries two equal weights by means of a small and 
very flexible silken cord which runs in a groove upon its circumference. 
This wheel, with its supporting apparatus, is placed upon the top of a 
frame seven or eight feet in height; and motion is given to the system 
of suspended and equipoised weights by placing upon one of the two a 
small additional weight, bearing a definite proportion to the whole equi- 
poised mass. The moving force is this additional weight; the mass 
moved will be many times this weight, and the velocity generated in a 
given time will be just as many times less than that which gravity would 
produce in a body freely falling for the same time. Thus, if the whole 
mass moved is sixty-four times as heavy as the added weight which fur- 
nishes the motive power, the velocity generated in one second will be 
one sixty-fourth of that produced in one second by free gravitation. 
And as that is known to be thirty-two feet (with a fraction which may 
for the present purpose be disregarded,) the velocity acquired in the 
experiment, under the circumstances supposed, will be thirty -two feet 
divided by sixty-four; that is to say, six inches. And as the space 
fallen through in the first second is only one-half as great as that which 
expresses the acquired velocity, the weights in the machine will only 
move through a space of three inches from rest in this first second in 
the experiment supposed. With a motion so deliberate it is possible to 
illustrate fairly the laws which govern the movements of bodies sub- 
jected to the action of constant forces. Yet there is still so much of 
inevitable inexactness in marking the instants limiting an observation, 
that the machine of Atwood, though extremely interesting and really 
serviceable for purposes of instruction, is hardly entitled to be called 
an instrument of precision. 

Another machine, designed by General Morin, for a purpose similar 
to that had in view by Atwood, has been received by physicists as a use- 
ful addition to their means of instrumental illustration. The essential 
part of this machine is a vertical cylinder, six or seven feet high, turn- 
ing easily upon its axis of figure, and driven by clock work and a de- 
scending weight. A wind-vane regulator serves to maintain uniformity 
of rotation. The cylinder is closely wrapped with white paper, which 
ought to be ruled with equidistant parallel lines, both horizontally and 
vertically. A weight which is perfectly free to fall when released from 



ILLUSTRATION OF LAWS OF FALLING BODTES. 489 

a detent at the top of the machine, is guided in its fall by a couple of 
wires stretched vertically, and carries in its descent a pencil of which 
the point is kept by a light spring in contact with the paper wrapping 
the revolving cylinder. At a given instant the detent is touched and 
the weight falls. The velocity of descent is accelerated, while that of 
rotation is uniform. The curve described by the pencil as the combined 
result of these two motions will be found, by measuring its co-ordinates 
on the paper, to be a parabola; and from this may be deduced the law 
regulating the fall. 

Another mode of deducing this law from observation was suggested, 
nearly thirty years ago, by Professor Wheatstone, in which the difficulty 
of noting the moments of commencement and end of the fall is over- 
come by calling in the aid of electricity. The rupture of an electric 
current drops the weight, and starts a chronoscope at the same instant ; 
the impact of the body at the end of the fall suddenly arrests the chrono- 
scope and records the interval of time elapsed. By increasing or dimin- 
ishing the distance fallen through, the relations are ascertained of space 
to time. 

In the present Exposition, an instrument is exhibited by Mr. Bour- 
bouze, of Paris, which, for the accuracy of its indications, seems to offer 
some important advantages over all the methods heretofore employed 
for illustrating the laws of falling bodies. Like Atwood's machine, the 
contrivance of Mr. Bourbouze has a pulley mounted on friction wheels, 
which carries upon the same axis a very light cylinder. The pulley 
also, as in the machine of Atwood, sustains two equipoised weights, 
and is put in motion by placing on one of these an additional weight. 
The cylinder above mentioned is covered with paper which is coated 
with lampblack from the smoke of burning turpentine. Opposite the 
cylinder is placed a diapason, one of the arms of which carries a tracer 
which touches lightly the smoked surface of the cylinder. The vibra- 
tion of this diapason, after being mechanically excited, is maintained by 
the attraction of an electro-magnet, of Avhich the circuit is alternately 
closed and broken by the vibration itself. The time of the vibration 
is known by the pitch of the resulting sound. Supposing that, during 
the vibration, the cylinder is put into rotation with a uniform velocity, 
the tracer will describe a sinuous mark in which the summits of the suc- 
cessive undulations will be equidistant. But if the velocity of rotation 
is accelerated, these successive intervals will be larger and larger, 
though still denoting equal intervals of time ; so that by a comparison of 
their lengths the law of velocity, as related to space passed over, may 
be easily deduced. In the use of this instrument, the loaded weight is 
placed at the highest point of the course, and after the vibration of the 
diapason has been established, the weight is suddenly set free. So long 
as it is accelerated by its load, the rotation of the cylinder is accelerated 
in like manner. If the load is intercepted by a ring, as in Atwood's 
machine, the rotation becomes uniform, maintaining the velocity last 



490 PARIS UNIVERSAL EXPOSITION. 

acquired; and these effects are visibly inscribed on the cylinder in the 
manner above explained. The cylinder admits of lateral displacement, 
so that several experiments may be performed before it becomes neces- 
sary to renew the covering of smoked paper. In order to mark with 
exactness the equal intervals of time, it is advantageous, before closing 
the circuit, to allow the cylinder to ran while the diapason is at rest. 
The trace described will then be a line without sinuosities. Afterwards, 
when the original arrangement has been restored and the experiment is 
performed in the manner explained above, the undulating line described 
by the tracer will cross the mean line previously traced at exactly equal 
intervals of time ; and these intersections will form more definite points 
of reference in measurement than are afforded by the summits of the 
undulations, since these necessarily become flatter and flatter in pro- 
portion as the velocity increases. This instrument cannot but prove to 
be a valuable contribution to the means of visibly illustrating the laws 
of gravity. 

II.— PXEITMATICS. 

OEISSLER'S AIR-PUMP WITHOUT VALVES. 

Several pneumatic machines designed both for exhaustion and for 
compression were present in the Exposition which deserve notice for 
their originality. Messrs. Alvergniat Brothers, of Paris, exhibited an 
apparatus called by them an " air-pump without valves," devised in the 
first instance, it is believed, by Geissler, and employed by him in the 
preparation of the tubes known by his name, but considerably modified 
in the details of construction by the present exhibitors. A variety of 
Geissler tubes were exhibited by this house, all of which were prepared 
by the use of this apparatus. The merit of this contrivance, of which 
the figure shows one of the simpler forms, consists in the fact that it 
suppresses entirely what is called by the French Vespace nuisible, and by 
the English, " dead space f making it possible to continue the exhaus- 
tion without limit, or to make it as nearly absolute as may be required 
for any purpose. 

The principal parts of this apparatus are. first, a glass tube, which 
must be as long at least as the barometric column, and which is enlarged 
near the top to a globe. The dimensions of this globe will depend 
somewhat upon the purpose for which the apparatus is to be used, bur 
will be limited by considerations of the strength of the material, since, 
as the first step in the process of exhaustion, the globe is to be filled 
with mercury. At a little distance above the globe is placed a three- 
way cock, by means of which the globe may be put into communication 
either with the continuation of the tube above, or with a lateral branch 
which opens to the atmosphere. This lateral branch is surmounted by 
a funnel, or bell-shaped termination. The direct tube makes a right 
angle and is open at its extremity. A second simple stop-cock is placed 



PNEUMATICS — GEISSLERS AIR-PUMP. 



491 



Fis:. 9(5. 



on its horizontal extension. The whole is firmly attached to an upright 
frame or plank. The open tube at top is to he connected by a caout- 
chouc continuation with the 
vessel to be exhausted. The 
lower extremity of the main 
tube is also open, and is con- 
nected with another stout 
caoutchouc tube, long 
enough to reach the level of 
the bell- shaped termination 
of the lateral branch above 
decribed. It is attached to a 
glass globe at least equal in 
capacity to the glass tube 
and its globular air chamber. 
At the top of the supporting 
frame is a bracket of suit- 
able form to sustain this 
globe $ and at the foot of 
the same support is another 
similar bracket, which in the 
figure is partially concealed 
by the caoutchouc tube. 

The mode of using the ap- 
paratus will now be easily 
understood. The proper con- 
nection having been made 
with the vessel to be ex- 
hausted, the uppermost stop- 
cock closed, and the large 
movable globe, or reservoir, 
having been filled with mer- 
cury, this last is placed on 
the upper bracket, as shown 

in the figure. The three-way Geissler's Air-pump without valves. 

cock is then turned so as to open communication between the upright 
glass tube and the lateral branch. The mercury descending the caout- 
chouc tube and rising in the glass tube, expels all the air from the appa- 
ratus, and enters the funnel ; the use of which is merely to prevent its 
overflow. At this moment the three-way cock is again turned so as to 
close the lateral opening, and the movable reservoir is transferred to the 
lower bracket. On opening now the upper stop-cock, the air in the vessel 
to be exhausted will be rarified by the descent of the mercurial column, 
and a certain proportion of it will fill the apparatus. The cocks are 
then to be restored to their original positions and the reservoir placed 
once more on the uppermost bracket. This process is not rapid, and 




492 



PAEIS UNIVERSAL EXPOSITION. 



is employed only in the exhaustion of small vessels or tubes for labora- 
tory purposes, or for the preparation of electrical apparatus. 

A larger form of the same contrivance is employed by the Messrs. 
Alvergniat, in which the tube of caoutchouc is dispensed with, and the 
reservoir is attached to a rigid tube of iron, the whole being secured to 
a solid plank or frame which is hinged at the foot of the fixed upright. 
This facilitates the raising and depressing of the reservoir ; an operation 
which is laborious, and which, when the reservoir is large, may even be 
hazardous. 

KEAVOGP/S 3IERCURIAL AIR-PU3IP. 

An ingenious pneumatic machine, designed, like the one above de- 
scribed, to suppress the dead space which limits the efficiency of ordi- 
nary air-pumps, was exhibited in the Austrian section of the Exposi- 
Fig, 97. tion by Mr. J. Kravogl, of 

Insbruck. The principle 
of this machine will be 
best understood by refer- 
ence to Fig. 97. It has a 
single cylinder, although 
it is capable of being con- 
structed with more than 
one. This cylinder, which 
is of glass, is reduced at 
the top to a narrow neck, 
and is surmounted by a 
funnel. In the neck of the 
funnel is a valve opening 
f^. upward. The cylinder con- 

jR^ ) tains a certain quantity 

of mercury. A plunger, 
of dimensions nearly equal 
to the capacity of the cyl- 
inder, enters it at the bot- 
tom and is raised in work- 
ing so as to occupy it al- 
most entirely. The mer- 
cury then fills the small 
annular space between the 
plunger and the wall of 
the cylinder, and also the 
space above the plunger 
Kravogl's Mercurial Air-pump. up to the valve. By this 

means the air is completely expelled; and as the valve is covered by a 
small quantity of mercury in the funnel, there is no danger of leakage. 
A lateral tube connects the cylinder with the plate of the pump on which 
the receiver rests. The point of uuion with the cylinder is a little above 




AIR-PUMPS. 493 

the level of the mercury when the plunger is at its lowest depression. 
Communication between the receiver and the cylinder is opened, when 
the plunger is in this position, by an automatic arrangement, of which 
one form is shown in the figure and will be easily understood, but which 
may take any most convenient form. The commencement of the upward 
movement closes this communication, which is not re-established again 
until after the air which has passed into the cylinder has been expelled 
and the plunger has once more returned to its lowest position. In prin- 
ciple, this machine is unexceptionable. Whether any unperceived dis- 
advantage attends its operation in practice, will be determined by experi- 
ence. It would be an obvious improvement to employ two cylinders 
instead of one. After the exhaustion has proceeded a little, the atmos- 
pheric pressure upon the plunger not only makes the working laborious 
in the downward movement, but makes it necessary to oppose a resistance 
to the upward stroke, except just at the close. This disadvantage does 
not exist in the large single-barreled air pumps of Eitchie, Deleuil, and 
others ; because in those, the piston is not exposed to the returning pres- 
sure of the atmosphere. But while a piston may be shut up in a closed 
cylinder, a plunger cannot be conveniently so ; and hence a pair of 
plungers counteracting each other by a connection like that of the pis- 
tons in the common double and open barreled air-pumps, would obvi- 
ously be preferable to the single-barreled machine exhibited. 

RICHARD'S AIR-PUMP WITHOUT VALVES. 

Mr. F. Richard, of Paris, entered upon the catalogue of the Exposition 
an air-pump under the name above written. The machine is one of very 
large proportions, and it was not actually present in the Exposition ; 
but its operation was witnessed in the workshop of the inventor, who 
obligingly explained its details and furnished drawings exhibiting its 
construction. The principle on which the efficacy of this machine 
depends is that of Babinet's double-exhaustion air-pump, but it is carried 
much further, so that the exhaustion as compared with that of a simple 
machine, instead of being, as in Babinet's pump, in the ratio of a con- 
stant to its square, is as the same constant to its eighth power. 

A simple pump unprovided with any expedient like that described in 
the apparatus of Alvergniat, or the pump of Kravogl above described, 
for getting rid of dead space, can carry exhaustion only up to the limit 
expressed by the ratio of this dead space to the entire capacity of the 
working barrel, the dead space included. Or, if s represents the dead 
space, and S the total space, d the limiting density of the air in the 
receiver, and D the density of the atmosphere at the same time, it will 
be true in the last limit that, 

d s 

The reason of this is found in the consideration that no air can be 
expelled from the cylinder by the piston when its density at the termina- 
tion of the stroke is only equal to that of the outward air. This is the 



494 PARIS UNIVERSAL EXPOSITION 

limit, even though the valves he opened mechanically and not by the 
elastic force of the air itself. But a quantity of air which, when occupy- 
ing the space s, has the density D, will, when dilated to fill the larger 
space S, have evidently a density equal to s : S — a proposition which 
verifies the equation foregoing. 

If, however, the air in the space s should have an opportunity opened 
to it of escaping, not into the atmosphere, hut into another space = S, 
which is practically a vacuum, it would immediately assume a density 
= s : S or d : D; and if the same state of things should continue to 
exist at the end of every stroke of the piston, the puinp would be practi- 
cally working not against an atmosphere of the natural density D, but 
against one of the reduced density d : D. And hence we conclude that 
exhaustion will go on until the final density in the receiver is to that 
against which it is working in the ratio d : D ; while this latter is at the 
same time to the natural atmosphere in the ratio d : D also. Or the 
ratio of density at final exhaustion to the density of the atmosphere at 
the same time is d 2 : D 2 . 

This result is obtained in effect in the double exhaustion pimrp of Mr. 
Babinet. The pump has two equal barrels, with pistons working alter- 
nately. One of these barrels discharges itself into the other, and this 
second one expels the air in this manner received into the atmosphere. 
This second pump, if worked alone, is capable of effecting an exhaustion 
of d : D. As the two work alternately, the first one throws its charge 
into this when the density of its contained air is minimum. That is to 
say, the first pump, or the one which communicates with the receiver, 
works against a density of d : D ; which, as we have seen, is the con- 
dition necessary to produce an ultimate exhaustion equal to d 2 : D 2 . 

We have only now to suppose this principle extended to a series of 
barrels, and the exhaustion possible to be effected by the series will be 
expressed by the ratio An : D n ; in which n represents the number of bar- 
rels. In the pneumatic machine of Mr. Eichard, eight barrels are thus 
connected in a series. The barrels are also very large, having each the 
capacity of six and a half cubic decimeters, or four hundred cubic inches 
(nearly seven quarts.) Mr. Eichard has also in operation a second pump 
of similar construction with only four barrels. 

The object for which these powerful machines were built, was to sub- 
serve the purposes of an extensive manufacture, carried on by the invent- 
ors of manometers for indicating the pressure of steam or other elastic 
fluids, and of metallic barometers, similar in form to those which bear the 
name of Bourdon. In these instruments the essential organ consists of a 
metallic tube in the form of a horseshoe, having a cross-section of len- 
ticular shape. Such a tube, when exposed to unequal pressures on its 
external and internal surfaces, varies its figure with the variations of 
pressure, the extremities of the horseshoe approaching each other with 
the increase of the external pressure, and vice versa. As constructed by 
Mr. Eichard, these tubes are very seusitive to atmospheric changes, and 
fulfill admirably all the ordinary purposes of a barometer. It was for a 



richard 7 s pneumatic machine. 495 

time a defect in the construction of these barometers that the tubes were 
deficient in elasticity and stiffness. Mr. Richard has happily overcome 
this difficulty, by the introduction within the tube of a steel spring of 
the same general form, which remedies the defect, and secures perma- 
nent uniformity of action. It is important that this spring, while within 
the tube and secured to it at both extremities, should not touch the 
interior walls. This condition the construction of Mr. Richard perfectly 
fulfills ; and his barometers may be recommended to all who wish an 
accurate and portable instrument, as being admirable in workmanship 
and entirely satisfactory in performance. Mr. Richard constructs a 
variety of models of his barometer, from a size not larger than a watch 
to one not less than a foot in diameter. These instruments are not to be 
confounded with the so-called aneroid barometer, which, in outward 
form, they somewhat resemble, and which it is not intended to disparage 
while doing justice to the merits of their rivals later in the field. The 
aneroid barometers have a reputation for reliability which is believed to 
be well deserved. 

The construction of Mr. Richard's eight-barreled air-pump may be 
gathered from the figures in Plate VIII. Figs. 1 and 2 in this plate 
furnish views in elevation ; 'Fig. 1 an end elevation, and Fig. 2 a side 
elevation. Fig. 3 is a plan representing the relative positions and the 
connections of the cylinders. From this last figure, it will be seen that 
the barrels are arranged in two rows. Their places are marked A. 
Tubes of caoutchouc connect the barrels at their bases, indicated by 
the letters R and R'. The first cylinder in the front row on the right is 
connected with the vessel to be exhausted, by means of the caoutchouc 
tube R', which is shown recurved toward the front. This cylinder com- 
municates with the one immediately behind it, through a shorter tube 
R, also of caoutchouc, of which the direction is at right angles to the 
length of the machine. This second cylinder communicates, by means 
of the diagonal tube R', with the next in order in the front rank ; this 
with the second in the rear rank, and so on, until finally the last cylin- 
der in the series communicates with the atmosphere by a valve opening 
outwards. Each one of the communicating caoutchouc tubes is bridged 
over by a bracket which is screwed down to the base plate. This 
bracket does not ordinarily compress the tube, but there is a piston 
beneath it, rising through the base plate of the cylinders, and carrying 
a broad cross-head, which, on being pressed upward, at a certain point 
of the movement of the pump, flattens the tube against the bracket, 
and closes the communication hermetically. A little consideration of 
the arrangement will show that it is necessary to the regular transmis- 
sion of the air from the vessel to be exhausted, to the extreme cylinder 
marked A 2 , and so to the atmosphere, that all the short direct commu- 
nications shall be closed, while the diagonal ones are open, and vice 
versa; and also that all the pistons in the front rank shall be rising, 
while those in the rear rank are descending, and vice versa. Hence the 
pistons which compress the short cross-tubes must act simultaneously ; 



496 PARIS UNIVERSAL EXPOSITION. 

and in the mean time, those designed to act on the diagonal tnbes will, 
for the moment, not be in action ; but immediately after, the diagonal 
tubes will be compressed, and the short direct tubes will be relieved. 

To show how these successive movements are effected, resort must be 
had to Figures 2 and 1. In Fig. 2, the direct tubes are shown under 
compression immediately in front of each cylinder, at E, E, E, E, and 
the diagonal tubes are shown in section uncompressed, at B 7 B 7 B 7 . The 
brackets over the tubes appear in this figure, marked V b' V V . The 
compressing pistons are also shown ; those beneath B 7 B 7 E, in connec- 
tion with the mechanism by which they are raised ; and those beneath 
E, B, E, E, incomplete, being controlled by another mechanism which 
is not shown. In Fig. 1, however, the nature of this mechanism is 
shown for both sets of pistons. 

To follow the connections of the gear- work, two cranks, X and X, at 
opposite extremities of the machine, by turning directly the pinions L, 
act on the gear-wheels K, and these gear-wheels, by means of a pinion 
I, on their common axis J, drive the gear-wheel in the middle of the 
mechanism, on the axis F. Upon this same axis F is the cam S, which, 
during half the revolution, acts through the lever d, turning on the 
pivot C 7 , and by means of the arm C 2 , raises the piston B 7 , with the 
effect of compressing the tube E between it and the bracket b'. Upon 
this same shaft F are two additional gear-wheels, marked Gr, which 
drive a similar and equal pair, similarly marked, (Fig. 1,) on an axis F 7 , 
parallel to F. External to the gear-wheels G are strong cranks E, 
which, by means of the long connecting-rods D, move the cross-head 
which carries the pump pistons B. These cross-heads move in the 
guides S, and each one of them carries four pistons. The pistons them- 
selves are constructed of dished leather. Upon the axis F 7 is a second 
cam, S 7 , which acts on the lever d', as S does on d, and effects the com- 
pression of the diagonal tubes E 7 , at the proper period of the revolu- 
tion. By observing the arrangement, it will be seen that these two 
cams perform their office alternately, the figure showing S 7 in action, 
while S is not. 

From the gear- work connections it will be manifest that the motion 
of the pump pistons will be slow; but this is not a disadvantage, consid- 
ering that the barrels are large and that the passages through which the 
air has to flow are narrow, while the velocity of flow, which decreases with 
the elasticity, becomes greatly reduced toward the close of the opera- 
tion. The exhaustion effected by the pump, however, is extreme : and 
when the capacity to be exhausted is not great, it is sufficiently rapid. 
It makes about three strokes to the minute; and in a receiver of the 
capacity of two gallons it will produce a rarefaction to one four-hun- 
dredth of an inch of mercury in five minutes. 

Other ingenious forms of valve have been employed by Mr. Richard 
in some of his pneumatic machines, which are illustrated in Figs. (>. 7. S. 
and 9, PI. VIII. Fig. 6 shows a discharge valve, /, which is maintained in 
place by the spiral spring g, aided by the pressure of the air in E, and 



PNEUMATICS DELEUIL'S FREE-PISTON AIR-PUMP. 497 

which is mechanically controlled by the stem//. To prevent leakage 
from the superior pressure of the external air, the stem and the metallic 
tube e through which it acts are surrounded by a tube of caoutchouc, 
which is firmly bound to both, but by its elasticity leaves to the stem 
sufficient movement. Fig. 7 shows the base of the cylinder to which 
this valve is attached, as seen from above. 

In Fig. 8 is seen a simpler and preferable form. In this, a a' is the 
duct through which the air escapes from the cylinder to the tube R; 
and J' J 7 is a plate of caoutchouc which is secured in place by the cap 
h screwed firmly down. A piston passing through the cap and operated 
mechanically, compresses the caoutchouc plate and closes the duct at 
the point J. If instead of a simple piston a screw be employed, this 
contrivance is a very effectual form of stop-cock. 

DELEUIL'S FREE PISTON AIR-PUMP. 

Probably the most remarkable pneumatic machine which appeared in 
the Exposition, or which has been yet constructed, is the free-piston air- 
pump, of Mr. J. A. Deleuil, of Paris. The peculiarity of this machine 
is that the piston works out of contact with the barrel of the pump, and 
of course entirely without friction. This piston is a metallic cylinder, 
and the barrel within which it moves is of glass. But though there is 
no contact between the surfaces, the space between them is exceedingly 
minute, being stated at the fiftieth part of a millimeter. It is of course 
necessary that the workmanship should be very superior, and that the 
strength of the whole machine should be such as to remove all danger 
of change of figure, or of any even very slight deviation of movement, 
or disturbance of the truly concentric adjustment. 

The efficacy of this machine depends upon the difficulty and slowness 
with which gases make their way through very narrow spaces. The 
film of air between the piston and the wall of the cylinder is practically 
confined there, and forms a kind of lubricating cushion. The only 
resistance, therefore, which the piston encounters in its movement, is 
that which arises from the unequal density of the air above and below 
it. Fig. 98 shows this machine in elevation. The piston is driven by 
means of the epicycloidal combination of La Hire, operated by a crank 
and fly-wheel. It is guided by a rod extending entirely through the 
barrel at bottom as well as at top. There are two valves at each end of 
the cylinder, one opening inward and the other outward. The outward 
opening valves both communicate with the same tube, which is recurved 
and united with the cylinder at both extremities. At the middle point 
of this tube, a branch leading from it may be connected with a con- 
densing apparatus ; so that the pump may be used for compression as 
well as for rarefaction. When used for the ordinary purposes of an air- 
pump, however, this branch is open to the atmosphere. On the other 
side, the two inward opening valves are similarly connected, and the 
branch tube on that side establishes communication with the receiver to 
be exhausted. But when the pump is employed to compress air, this 
32 i A 



498 



PARIS UNIVERSAL EXPOSITION. 



branch is open in its turn to the atmosphere. The valves as drawn in 
the figure are operated by the elasticity of the air. But in the con- 
struction now given to this part of the apparatus, they are opened and 
shut mechanically by the piston itself. For this purpose, there are 
introduced two cylindrical rods passing through the piston and reaching 
from end to end of the cylinder, but capable of a slight longitudinal 




Deleuil's Free-piston Air-pump. 

movement as the piston changes its direction. This movement opens a 
valve at one end and simultaneously closes the corresponding one at 
the opposite end; but this change having been effected, the rod remains 
stationary, the piston sliding on it as it continues its movement. The 



deleuil's free-piston air-pump— acoustics. 491) 

particular contrivance here described is not peculiar to Mr. Deleuil's 
pumps, however, as it has been often employed before. 

The interior bore of the barrel must, of course, be very truly cylin- 
drical and well polished. The piston is, in length, more than equal to 
its diameter. When the pump is used for compression, a greater length 
of piston is employed than is necessary for exhaustion. In point of 
fact, in this case, the difference of pressure on opposite sides of the 
piston becomes several times greater than it can be when the machine 
is employed only to produce a vacuum. There is no difficulty in carry- 
ing the condensation, in the course of a very few minutes, as high as 
five or six atmospheres. On the other hand, exhaustion is effected with 
remarkable rapidity. With a machine having a cylinder of four and a 
half inches in diameter, a twenty gallon receiver may be exhausted 
down to a pressure of less than half an inch of mercury in five minutes. 
Exhaustion may be carried lower than to the tenth of an inch of mercury. 

The figure shows that the piston has not a continuously cylindrical 
surface from top to bottom. It is cut by grooves of very slight depth, 
and about half an inch apart. These grooves fulfill, apparently, a very 
useful function. Suppose the difference of pressure below and above 
the piston to be very great — the excess being, for example, below ; the 
velocity with which the air tends to escape on the upper side, will be 
much less than that with which it tends to enter the narrow space 
between the piston and cylinder on the lower. But before this superior 
velocity can be transmitted beyond the first groove, this groove must be 
filled with air of density equal to that below the piston. And before 
the same velocity can be propagated beyond the second groove, this 
second groove must be filled in like manner. As the movement is slow 
even when the pressure is greatest, it will take a much longer time to 
transmit through all the intermediate grooves to the upper limit of the 
piston the tendency to movement which exists at the lower limit, than 
it would do if the piston were quite continuously cylindrical ; and thus 
we have the paradoxical effect of a packing, produced not by adding to 
the substance of the piston, but by taking from it. It is found, in fact, 
that the working of the pump may be interrupted a sensible time with- 
out turning a stop-cock, and yet without vitiation, by the infiltration of 
air between the piston and cylinder, of the vacuum already secured. 

III.— SOUND. 

No branch of modern physical investigation has been productive of 
more numerous interesting results than acoustics. And in no branch of 
experimental inquiry have investigators been dependent for their appa- 
ratus upon a smaller member of able constructors. This subject was rep- 
resented in the Exposition almost exclusively by a single exhibitor, Mr. 
Eudolph Kcenig, of Paris. On the other hand it may be said that Mr. 
Koenig's exhibition was so complete and admirable as to leave nothing 
to desire. Inasmuch as the laws which govern the production and the 
mutual influence of sounds are strictly mechanical, they admit of being 



500 PARIS UNIVERSAL EXPOSITION. 

demonstrated by methods which are not acoustic in the sense of being- 
dependent on the sense of hearing ; and accordingly the most striking 
illustrations of acoustic phenomena which have been recently devised, 
are addressed rather to the eye than to the ear. These are either 
graphic, being the permanent delineation, upon a properly prepared 
surface, of the path of a vibrating point ; or optical, presenting the visi- 
ble image of the same path, as seen through a microscope, or thrown in 
greatly magnified dimensions upon a screen ; or, finally, optical and 
mechanical at the same time, exhibiting visibly the varying conditions 
of a vibrating body of air by the effect produced upon jets of flame. 

At the same time, methods of investigation strictly acoustic in char- 
acter have been pursued in recent years with great success ; and in this 
branch of inquiry no one has made more valuable contributions to the 
ascertained facts of science, or to the instruments of research, than Pro- 
fessor H. Helmholtz, of the University of Heidelberg. One of the most 
interesting instruments exhibited by Mr. Kcenig was the double siren of 
Helmholtz. The simple siren of Cagniard de la Tour is well known, 
and may be described as consisting of a cylindrical brass box or wind- 
chest, into which a blast of air is introduced by a tube through the bot- 
tom, while the top is perforated by a series of equidistant apertures 
arranged in a circle. A circular plate, similarly perforated, turns freely 
on its center almost in contact with the top of the wind-chest, so that it 
alternately opens and closes the passages for the escape of the air. 
according as the two sets of apertures coincide, or the contrary. The 
apertures are inclined in direction in the same manner as the directrices 
and pallets of a turbine wheel; that is to say, so as to give to the 
escaping air the greatest effect in imparting rotation to the freely 
moving disk. When air under pressure is admitted to the wind-chest, 
the rapid succession of impulses produced by its intermittent escape 
generates a musical note which continues to rise in pitch until the 
increasing resistances balance the impelling force : after which the pitch 
remains constant. The axis of the disk carries a screw-thread by means 
of which a set of register dials may be operated, recording the number 
of revolutions made in a given time. This recording apparatus may be 
thrown into gear with the screw, or thrown out, at the pleasure of the 
experimenter. If it is desired to ascertain how many impulses to the 
second are necessary to produce a note of a given pitch, the wind pres- 
sure must be adjusted in such a way as to maintain that pitch steadily. 
Afterwards, the recording apparatus is to be thrown into gear and 
allowed to run for a determinate length of time, when it must be 
detached. The difference between the initial and final readings of the 
register will give the number of the revolutions of the disk : and this. 
multiplied by the number of perforations in the circle, will give the 
total number of impulses. Dividing then the number of impulses by the 
number of seconds embraced in the observation, there will be found the 
number of complete vibrations or sound waves per second, correspond- 
ing to the given pitch. 



ACOUSTICS HELMHOLTZ'S DOUBLE SIREN. 501 

The siren invented in 1827 was improved by Opelt in 1834, by See- 
beck in 1819, and by Dove in 1851. In these improved forms the revolv- 
ing disk was provided with a number of sets of circular perforations, 
the object being to illustrate the effects of harmonic and interfering 
sounds, the coalescence of impulses from many sources in producing a 
single sound, the impressions resulting from impulses not isochronous, 
and the so-called combination tones occurring when the beats of discord- 
ant notes are too rapid to be separately distinguished by the ear. The 
most elaborate of these instruments is that of Seebeck, which was exhib- 
ited, in greatly improved form and on a large scale, by Mr. Kcenig. In 
this instrument the rotation is produced by mechanism, and not by the 
blast. The rotary disk may also be removed and replaced by another 
differently perforated: and instead of a wind-chest, twelve port-vents 
connected with an air reservoir or blowing machine, by means of caout- 
chouc tubes, are employed to conduct the air to the apertures in the 
disk. These, of course, admit of adjustment to the different series of 
perforations on which it is desired to experiment. There are nine dif- 
ferent disks, and each one carries a number of circles of apertures, some 
of them as many as eight. 

HELMHOLTZ'S DOUBLE SIBEN. 

The double siren of Helmholtz is the last and most interesting of the 
instruments of this class. It consists of two sirens, one of them placed 
in an inverted position directly over the other, and each constructed on 
the plan of that of Oagniard de la Tour, as modified by Dove ; that is, 
having four concentric sets of perforations, provided with registers to 
allow of their being used together or separately, as may be desired. 
The two revolving plates are also connected by a common axis, and thus 
revolve together. In Dove's siren the numbers of perforations in the 
successive circles were eight, ten, twelve, and sixteen, corresponding to 
the tome, third, fifth and eighth of the musical scale. In the double 
siren, one of the disks is perforated with eight, ten, twelve, and eighteen 
holes, while the other has nine, twelve, fifteen, and sixteen. The exter- 
nal circle on each disk gives a note which is the octave of that corre- 
sponding to the inner circle on the other. The second and third circles 
in each disk give harmonics of the inner one ; and by combining the 
numbers in the two disks by pairs, many concords may be produced. 
But the most important peculiarity of this instrument consists in the 
introduction of a simple mechanism by means of which the upper cylin- 
der or wind-chest may be rotated around its vertical axis while the 
instrument is in operation ; a peculiarity which adapts it to many 
curious illustrations of acoustic principles. A crank acting through 
gear work, enables the experimenter to effect the rotation ; and the 
extent of the angular advancement of the wind-chest at any moment, is 
shown by an index on a divided circle. 

Supposing the air to be admitted to but a single circle in this upper 
cylinder, the lower at the same time not being in operation, and the pitch 



502 PARIS UNIVERSAL EXPOSITION. 

having been made steady, the rotation of the wind-chest produces an 
elevation or depression of the pitch according as the direction of its 
movement is opposed to or in coincidence with that of the disk. In the 
first case the intervals between the impulses are shortened, and in the 
second they are lengthened, by the effect of the double motion, and the 
number per second is correspondingly increased or diminished. 

When the air is admitted to the circles in the two disks which are 
similarly perforated, (those having twelve apertures in the circle,) the 
instrument admits of an instructive study of the effects of the inter- 
ference of equal waves, or of the resultant sound produced by the super- 
position upon each other of waves of equal length but in different phases. 
When the openings in the two wind-chests are exactly in the same 
azimuths, the impulses coincide, and the intensity of the resultant sound 
is equal to the sum of the intensities of the separate sounds ; but when 
the upper wind-chest is displaced from this position by turning the crank, 
the intensity of the sound diminishes in consequence of interference, 
until the angular displacement is equal to half the distance between the 
successive apertures, when the intensity is minimum. The same ingen- 
ious instrument serves for the investigation of the interferences of 
unequal waves, of combination tones, and of many other interesting 
acoustic phenomena. 

HELZUHOLTZ'S RESONATOR. 

Another important acoustic instrument invented by Prof. Helmholtz 
is the resonator, an instrument designed to facilitate the analysis of com- 
pound sounds or notes. It has been clearly demonstrated by Prof. 
Helmholtz that scarcely a single sound in nature, and scarcely a note of 
music by whatever instrument produced, is made up of a simple series 
of isochronous impulses. Musical notes are accompanied by their har- 
monics, or, as the Germans call them, their over-tones. To the compound 
note thus produced they apply the term clang ; to the simple note, tone. 
As the effect of a note upon the ear will be sensibly modified by the num- 
ber and order of the over-tones which accompany it, we are accustomed 
to speak of these modifications without being conscious of their cause. 
as the qualities of sound; an indefinite term, which ought to be replaced 
by a better. Instead of quality, the French say timbre, the stamp or 
the ring; and the G-ermans, still better. Klangfarbe, sound color. 

It is a curious fact that the notes which we call brilliant owe their 
Klangfarbe to overtones related to the fundamental, as the odd numbers, 
three, five, seven, &c; while dull or muffled tones, such, for instance. 
as those of stopped organ-pipes, derive their character from overtones 
having ratios derived from two and its powers, four, eight, and so on. 
The brilliancy of the piano-forte is obtained by causing the hammers 
to strike the strings at a point about one-seventh of the total length 
from the end. The contrast of character between the note thus pro- 
duced and that which is obtained by striking the string in the middle 
is very strongly marked. 




ACOUSTICS HELMHOLTZ'S RESONATOR. 503 

When the air within a confined space, as a tube, is set into vibration, 
there is produced a clang, and not a tone. The fundamental tone in the 
clang- is that which corresponds to the smallest number of vibrations 
per second of which the mass of air is capable. In an ordinary organ 
pipe it is almost impossible to produce a tone without a clang. It can 
only be accomplished in the case of stopped pipes of large cross section 
feebly blown. But Helmholtz has found that a spherical or nearly spheri- 
cal cavity, or a wide and short cylin- 
drical tube narrowed at the end, will 
have a strong fundamental tone ordina- 
rily heard alone; and that the over- 
tones of such a cavity are excited with 
difficulty, and when excited are very 
faint. Upon this fact rests the con- 
struction of the resonator, which is 
shown in the accompanying figure. This 
is nearly spherical in form, having an 
opening on one side to the air, and a tube 
at the other, which is adapted to the 

ci ,1 • • , i Helrnholtz's Resonator. 

ear. Supposing this instrument care- 
fully fitted to one ear, while the other is stopped against all sounds, 
it will be observed that most of the words of ordinary speech, and most 
musical notes, are only faintly heard. But whenever the speaker or 
singer happens to strike the peculiar or proper note of the resonator, the 
sound will be so suddenly and singularly reinforced as to be almost 
startling. Now this effect occurs not only when the proper note of the 
resonator corresponds to the fundamental note of a clang, but also when 
it corresponds to an over-tone. It is possible, therefore, by means of a 
series of resonators, adapted to all varieties of pitch, to analyze the clang- 
sounds of music, and to find out what is that kind of composition which 
imparts to the notes of different instruments their characteristic quality, 
Klangfarbe, or sound-tint. This Professor Helmholtz has done ; and he 
has shown that the single tones which make up any clang, when separately 
heard in their proper resonators, are perfectly indistinguishable as to 
quality, whether they proceed from wind or from stringed instruments, 
from brass or from wood, from reeds or from open embouchures. Each 
resonator of Helmholtz is adapted to the detection of only a single tone, 
but this ingenious experimenter has succeeded in the construction of a 
compound resonator formed of three tubes sliding one within the other, 
by means of which the volume of air may be varied so as to adapt it to 
tones of different pitch. By one of the sliders large variations may be 
made, while by the other, which is governed by a rack and pinion move- 
ment, the instrument may be adjusted more exactly to the pitch which 
the first adjustment only attains proximately. It has been found prac- 
ticable even to construct a resonator capable of being changed in pitch 
by opening and closing holes with the fingers, as in playing upon a valve 



504 PARIS UNIVERSAL EXPOSITION. 

trumpet or clarionet; and the curious consequence follows, that an 
experimenter armed with this instrument may, in the confused roar of a 
cataract or of a crowd, regale his ear with a melody inaudible to others, 
by sifting as it were the proper notes out of the general din. The 
instrument, from the fact that it originates no sound itself, has been 
called the melodeon aphone, the voiceless melodeon. 

Eesonators are constructed by Mr. Kcenig of great variety of pitch. 
He furnishes for demonstrations a series of nineteen, embracing the prin- 
cipal harmonics from G in the bass clef to E in the third octave above. 

scheduler's tonometer. 

A striking part of the exposition of Mr. Kcenig was also Scheibler's 
tonometer, an apparatus for determining the exact number of vibra- 
tions concerned in producing a given tone, and also designed for use in 
tuning musical instruments. In this latter application it enables a per- 
son without the slightest pretense to a " musical ear, 7 ' to tune any instru- 
ment as accurately as the most accomplished musician. Scheibler's 
original apparatus consisted of sixty-five sounding-forks, or diapasons, 
beginning with in the treble clef, a pitch corresponds g to 512 simple 
vibrations, and extending to the above, corresponding to 1,024 simple 
vibrations. There are therefore sixty-four intervals, and as the numbers of 
vibrations increase in a uniform arithmetical series, the common differ- 
ence is eight. Any two of these diapasons adjacent to each other when 
sounded together will give four beats per second. To determine, there- 
fore, the pitch of a given string, its note is compared with the notes of 
the diapasons nearest to it in sound. By counting the resulting beats 
it will soon be referred to a place between some given two of the series, 
and then, by comparing the number of beats made with each of these 
two successively, its exact place will readily be inferred. In tuning a 
string to a given pitch an analogous process is pursued. If the string 
is to have precisely the same pitch as one of the diapasons of the series, 
it is not compared with that one, but with the one immediately above 
and the one immediately below. It must be so strained as to beat four 
times per second with either. If it is to be half- way between the two. 
it must be brought to beat twice per second with each. If it is to divide 
the interval as one to three, the number of beats must be one per sec- 
ond with the nearest and three per second with the other. Thus, if a 
string is to be tuned to the pitch A in this octave, this will require, as 
referred to the English concert pitch, 888 simple vibrations to the sec- 
ond, and will correspond exactly to the forty-seventh diapason of the 
series. The comparison must therefore be made with the forty- sixth 
and the forty-eighth. Eeferred to the French standard it will require 
870 vibrations to the second. The forty -fourth diapason gives 864 to 
the second, and the forty-fifth 872. The desired pitch divides the inter- 
val (8) into two lesser intervals, which are as six and two, or as three 
and one. It must therefore make three beats with the forty-fourth dia- 
pason and one beat with the forty-fifth. 



ACOUSTICS — TONOMETERS. 505 

The Scheibler tonometer, as exhibited by Mr. Koenig, was extended 
greatly beyond the limits above indieated, and was, in fact, made to cover 
the entire range of audible sounds. Thirty-two (thirty-one perhaps more 
exactly) simple vibrations, or sixteen successive sound waves, per sec- 
ond, is the smallest number which produces a continuous impression upon 
the ear. The upper limit of audible sounds was fixed by Savart at forty- 
eight thousand per second. Helmholtz placed it as low as thirty-eight 
thousand. Marloye imagined that he had proved it to be not lower than 
sixty-four thousand; but the laborious experimental determinations of 
Koenig have demonstrated that it is not constant in different individuals, 
and that it is in general between forty-five thousand and fifty thou- 
sand. With advancing age, sensibility to sounds of more than thirty- 
two thousand simple vibrations per second diminishes. 

Koenig's extended tonometer, as exhibited, embraced three hundred 
and thirty diapasons, carrying the pitch up to 4,096 simple vibrations 
per second. To these were added eighty-six straight steel rods for the 
higher pitches from 4,096 to 8,192 vibrations; these two series united 
embracing the entire range of notes employed in music. For tones still 
higher he had added rods corresponding to wider intervals than those 
of the tonometer proper, and representing only the notes of the com- 
mon chords of the next three superior octaves. 

For the four lowest octaves of the tonometer there were provided only 
two diapasons each ; but these were made in effect equivalent to sixty- 
five by having weights attached, which, sliding up and down upon the 
limbs, and being fixed by clamps at pleasure at the different points of a 
scale divided into sixty-four parts, produced as many variations of pitch 
within the limits of the octave. Thus the heaviest pair, which gave the 
notes corresponding to the numbers from 32 to 64 per second, would 
furnish intervals differing by only half a simple vibration, or one beat 
in four seconds. The second pair (64 to 128) gave intervals of one vibra- 
tion, or one beat in two seconds. The third (128 to 256) gave intervals 
of two vibrations, or one beat per second; and the fourth (256 to 512) 
gave intervals of four vibrations, or two beats per second. 

After these came the series of sixty-five diapasons, giving four beats 
per second, and going up from 512 to 1,024. 

From 1,024 to 2,044, eighty-six diapasons, or eighty-five intervals of 
twelve vibrations each, very nearly complete the octave from C 2 to C 3 . 
The exact octave C 3 would be 2,048. These intervals give six beats per 
second. 

From 2,044 to 4,096, there are required, for intervals of the same mag- 
nitude and giving the same number of beats, one hundred and seventy- 
two diapasons and one hundred and seventy-one intervals. 

After tbis come the straight rods, which are substituted for diapasons 
on account of the increasing difficulty of construction for notes of so 
high a pitch. These are excited by rubbing, and the pitch is that 
which corresponds to longitudinal vibration. The number of these is 



50 1) PAEIS UNIVERSAL EXPOSITION. 

eighty-six. The intervals are forty-eight vibrations, giving twenty-four 
heats to the second. 

Ten more rods give respectively 8,192, 10,240, 12,288, 16,381, 20,480, 
24,576, 32,768, 40,960, 49,152, 65,536, simple vibrations to the second; cor- 
responding to the notes C 5 E 5 G 5 C 6 G 6 G 6 C" E 7 G 7 C 8 . The sound C 8 is 
inaudible to all persons, as is probably G 7 . These ten vibrate laterally. 

GRAPHIC REPRESENTATION OF VIBRATIONS. 

The graphic method of observation of the vibrations of sounding- 
bodies, consists in attaching to the body under examination a delicate 
tracer, adjusted so as to touch lightly a smooth surface which has been 
blackened over a smoking name. This surface is made to move uni- 
formly under the touch, and the tracer leaves behind an undulating 
path, of which the form varies with the character of the vibration. To 
show the effects of combined parallel vibrations, equal or unequal in 
time, two diapasons may be used, both placed horizontally, with their 
stems Id opposite directions, and with the planes of their forks also hori- 
zontal. The surface on which the trace is to be made is attached to one 
limb of the lower diapason, and the tracer to the corresponding limb of 
the upper. Then both of them being excited, the one which carries the 
tracer is moved steadily in the common direction of their lengths, and 
the trace exhibits the resultant effect of the vibration. 

When the resultant of two vibrations at right angles to each other is 
to be obtained, the two diapasons are placed so that their axes may be 
at right angles ; but in other respects, the arrangements above described 
remain essentially unaltered. 

Another mode of obtaining graphic representations of the move- 
ments of vibrating points is to wrap a sheet of smooth paper round a 
cylinder which is provided with a clock-work movement : and then, 
having prepared its surface in the manner above mentioned, to bring 
the tracer into contact with this surface. By giving to the cyliuder a 
gradual movement in the direction of the axis, which may be effected 
by means of a coarse screw-thread on the axis itself, the trace will form 
a spiral on the cylinder, and the entire sheet of paper may be made 
available for experiment without troublesome adjustments. 

This method of studying vibrations has been generalized in the 
instrument called the phonautograph, or phonograph, by Scott and 
Kcenig, an instrument in which the tracer is moved by the vibration of 
a circular stretched membrane, which is itself excited by sonorous 
waves proceeding from any sounding body, as a bell, a diapason, a 
musical instrument, or the human voice. In order to intensify the 
impulses upon the membrane, this is fixed in the focal point of a large 
hollow paraboloid, truncated at the apex. The sounding body is placed 
in front of the paraboloid, and the receiving cylinder is brought into a 
convenient position at the opposite extremity to receive The trace. 
With this apparatus very interesting results have been obtained. In 



OPTICAL INVESTIGATION OF VIBRATIONS. 507 

order to determine the time of vibration of the several sounds under 
examination, as well as the forms of the paths, a diapason of known 
pitch, placed near the receiving cylinder, traces an independent curve, 
the undulations of which serve as time markers. Instead of a parabo- 
loid, Mr. Scott originally employed a large ellipsoid, placing the sound- 
ing body in one focus while the membrane occupied the other. This 
form of the apparatus is convenient for some purposes, and it has the 
advantage of giving a more powerful reflection ; but for experiments on 
musical instruments, or on sounds proceeding from bodies which cannot 
be conveniently introduced into the cavity, it is less convenient than 
that above described. 

Mr. Koenig not only exhibited these instruments, but also a very 
interesting album containing a great variety of curves of curiously com- 
plicated but symmetrical character which had been traced by means of 
them, showing how the over-tones of clangs manifest themselves as 
superposed upon their fundamentals; how vibrations of slightly unequal 
times alternately extinguish and reinforce each other, (giving in fact a 
visible picture of the beats,) and serving in many other respects as a 
curious and instructive study. 

The optical method of investigating vibrations was first employed by 
Lissajous, and was described by him in a communication made to the 
French Academy of Sciences in 1855. He has since considerably modi- 
fied and perfected it. It will be understood by supposing a small mirror 
of polished metal to be attached to one limb of a diapason, fixed by its 
stem in a firm stand, and placed in a dark room into which a ray of sun- 
light is admitted through a small aperture. The ray is received upon the 
mirror and reflected upon a white screen. To give sharpness and bril- 
liancy to the image, the light is made to pass through a convex lens of 
long focus, which is suitably adjusted to bring the focal point upon the 
screen. If the diapason is then excited, the slight movement of the 
mirror will be greatly magnified in the image upon the screen ; and 
owing to the persistency of the impression on the eye, the point will be 
apparently transformed into a straight line. If now a second diapason 
similarly provided with a mirror be interposed in the path of the reflected 
ray, a second reflection will take place ; and if the new image be simi- 
larly received upon a screen while both diapasons are vibrating, the path 
described may take a variety of forms dependent on the position of 
the axes of the diapasons, upon their times of vibration, and upon the rela- 
tion of the vibrations to each other in respect to phase. Supposing the 
two axes at right angles, and the phases identical or opposite, while the 
times are equal, the visible path will still be a straight line ; but it will 
be inclined at an angle of forty-five degrees to the directions of the two 
component vibrations. Supposing that the phase of one is one-qnarter 
advanced upon that of the other, the result will be a circle. All the 
other relations of phase will in this case give elliptical figures. When 
the times of vibration are different, the paths described are much more 



508 



PAEIS UNIVERSAL EXPOSITION. 



various, increasing in complication with difference of phase, according as 
the ratios of the times are expressible by less and less simple numbers. 
The diagram annexed represents some of the figures obtained with two 

Fig. 100. 








diapasons whose times are as three to four, representing the chord of a 
fourth. The first of these appears when the initial difference of phase 
is zero ; the succeeding ones correspond to differences of phase equal to 
the fractions ^-, yL, J., and i of the larger vibration ; that is to say, they 
make their appearance if, when the shorter vibration begins, the longer 
is advanced by the amounts of these several fractions. 

Fig. 101. 




Lissajous's Comparator. 

The apparatus here described is adapted to exhibit the vibration fig- 
ures to several observers at once. But as it may sometimes be desira- 



MECHANICAL EFFECTS OF VIBRATIONS. 509 

ble to study the vibrations of bodies to which mirrors cannot be attached, 
as for instance, of stretched strings, Mr. Lissajous has contrived an 
ingenious apparatus which he calls his comparator. This, which is rep- 
resented in the accompanying figure, consists of a diapason, to one limb 
of which is attached the object glass of a compound microscope; the 
body of the microscope being detached and supported by an independ- 
ent stand. If the diapason be thrown into vibration, the image of any 
small object seen through the microscope will appear to have a similar 
motion, which will be magnified by all the power of the instrument. 
Let the object be itself a point in a vibrating body, having its direction 
of vibration at right angles to that of the object-glass, and the combina- 
tion of the two motions will produce figures, from the analysis of which 
the character of the vibration of the body observed may be deduced. 
When the vibrating body is a string, or other object without conspicuous 
points suited to be used in the comparison, it is necessary to mark it in 
some manner. Different observers have adopted different expedients 
for this purpose; but in order to avoid loading the body or altering its 
condition by adding coloring matters, Mr. Lissajous, in the case of 
strings, has employed a cylindrical lens to throw a sharp line of light 
across the object. This creates a brilliant point moving with the string 
without in any manner disturbing its mode of vibration. 

In order to maintain the vibration of the diapason for an indefinite 
length of time, without being under the necessity of exciting it mechan- 
ically, Mr. Lissajous has also introduced an electro-magnet to act inter- 
mittently upon one of the limbs, the circuit being alternately closed and 
broken by means of an interrupter carried by the limb itself. The man- 
ner of making electric connection with the limb is shown in the figure ; 
but the interruptor itself, which is a short bent wire attached to the 
end of the limb, and dipping into a cup of mercury, is not represented. 

ACOUSTIC FLAMES. 

The acoustic methods founded on the mechanical effects of vibrations 
in the air upon gas flames are among the most recent as well as most 
remarkable contributions to this branch of investigation. It has long- 
been a familiar laboratory experiment to excite musical notes in a tube- 
by holding it over a burning jet of hydrogen gas. The explanation 
originally given of this phenomenon was to attribute it to the intermit- 
tent condensation of the watery vapor generated by the combustion. 
Faraday showed, however, that the sounds continued to occur, though 
the apparatus and the air in the tube were raised to a temperature 
above 212° F j and that carbonic oxide might be substituted for hydro- 
gen without preventing the success of the experiment. The true cause 
is probably the friction of the gas against the orifice through which it 
escapes 5 though Professor Tyndall ascribes it to the friction of the air 
against the flame. Professor Tyndall has himself shown that a long 
upright tube filled with water and discharging itself through a small 
orifice at the lower end, will emit a soft musical sound as the water 



510 



PARIS UNIVERSAL EXPOSITION. 



descends. The movement of bodies nibbing against each other is never 
steadily continuous; but the effects of inertia or other controlling 
causes often render the alternations of acceleration and retardation 
synchronous and regular. If these intervals correspond with the natu- 
ral vibration- times of the rubbing bodies, or of others in contact with 
them, very slight forces may by gradual cumulation produce striking 
effects. The friction of a jet of gas against the orifice by which it 
escapes, may be insufficient in itself to excite vibration in the column of 
air contained in the tube surrounding it ; but when the flame is present, 
the inequalities in the development of heat occasioned by the varying 
rapidity of combustion furnish a large reinforcement to the original 
sole disturbing cause. The very slight and at first even imperceptible 
tremor of the air thus produced reacts itself upon the combustion, con- 
stantly increasing the inequality just spoken of, as is even visible in the 
flutter of the flame, and the vibration becomes presently strong enough 
to be audible. Professor W. B. Rogers, of Boston, supposes that the 
immediate cause of the vibration is to be found in the periodical explo- 
sive combustion of the gas, and that the cause of the periodicity is the 
variable rapidity of escape of the gas from the orifice, which is imputed 
above to friction. Perhaps this theory might be regarded as the most 
plausible, if the facility with which the sounds are produced by carbonic 
oxide were sensibly less than is the case with coal gas. The question 
may be considered to be still, to a certain extent, unsettled. 

It is a curious fact that when a tube is 
thus excited to sing by means of a flame, 
the flame itself, though seemingly constant, 
is actually extinguished and re-kindled at 
every vibration. The proof of this was first 
shown by Professor Tyndall, by means of 
an optical arrangement extremely simple in 
itself, though very striking in the effects it 
produces. The experiment is made in a dark 
room. The tube employed is blackened in 
every part except on one side just opposite 
the point where the gas jet is to be placed. 
In front of the tube at this point is placed a 
concave mirror which is capable of being 
turned around a vertical axis. A screen is 
also adjusted at a distance suitable to re- 
ceive the image of the flame produced by 
the mirror. So long as the tube is silent, 
as it will usually be when the flame is larger 
than the experiment requires, the rapido scil- 
lation of the mirror around its vertical axis 
Rogers's Revolving- Jet. will pre duce upon the screen the appearance 
of a continuous band of light; but when, by gradually reducing the 
flame, the tube is made to sing, this band will be immediately broken 



Fig. 102. 




ACOUSTICS SINGING FLAMES. 511 

up, and in its place will appear a row of entirely separate and distinct 
images of the flame. Professor Eogers has very beautifully varied this 
experiment by dispensing with the mirror, and employing a bent gas 
tube, which is made to revolve rapidly within the singing tube of glass 
by means of a pulley and band as represented in the figure. The glass 
tube may be several inches in diameter ; but the experiment succeeds 
perfectly with one of two inches. When the jet is put into rotation 
while the tube is silent, the flame forms a continuous circle ; but the 
moment the tube begins to sing, the circle breaks up into a crown of 
minute flames, resembling a string of pearls. 

Mr. Kcenig presents a pretty variation of this experiment. In every 
tube there are one or more points where the presence of the flame excites 
the note with greater facility than elsewhere. There are other points 
where the sound is excited only with difficulty, or not at all. Between 
these there may be found, by trial, points which may be called points of 
unstable equilibrium, where the tube is just ready to sing, but needs, as 
it were, to be helped. When a tube is in this condition, it is sufficient 
to strike its proper note with the voice or with an instrument, and it will 
immediately respond. A tube can thus be spoken into music from a 
considerable distance. Mr. Koenig prepares two tubes of the same pitch, 
into one of which he introduces the revolving jet, while the other one 
has a fixed jet. The first of these is brought almost to the singing 
point, and the jet is put into revolution. The appearance presented by 
the flame is of course a continuous circle. The other tube is then brought 
to the singing point ; and the moment its note is heard, the first responds, 
and at the same time, in place of the luminous circle, displays its string 
of pearls. 

Mr. Koenig also prepares the apparatus of Schaffgotsch, for demon- 
strating the mutual influence of singing flames. A small gas jet is 
placed at a little distance beneath a circular burner, open in the middle 
in the manner of an Argand's lamp, which carries a ring of jets. Another 
similar small burner is placed within a tube of glass at the point proper 
to excite it to sound. This and the small exterior jet are lighted, but 
not the circular burner. If the jet in the tube is too feeble to excite the 
note, the tube may nevertheless be made to sing by striking the note 
with the voice ; but the reaction of the vibration upon the flame will be 
so strong as to extinguish it. By re-lighting it and giving it greater 
power, it will start the note itself, and then the effect upon the external 
flame will be such as to make it apparently leap up and become extinct 
in turn ; but in the mean time it will light the circular burner above it. 
Another apparatus of Count Schaffgotsch consists in a pair of tubes 
slightly out of unison, each being provided with its own singing flame. 
When these are both excited near to each other, the beats produced by 
the discord will be very audible ; and simultaneously the intervals of 
the beats will be visibly marked by corresponding oscillations of the 
flames. 



512 



PARIS UNIVERSAL EXPOSITION. 



Fig. 103. 

IIP' 



Mr. Koenig lias also availed himself of the sensibility of flames to 
vibration, to illustrate the difference of condition of the several parts of 
a vibrating column in a tube, by marking the points of the nodes and 
the positions of the ventral segments. Tubes pre- 
pared for the purpose were exhibited by him, one of 
which is shown in the accompanying figure. To the 
side of the tube are affixed little gas-chambers with 
a jet attached to each, the chamber being closed on 
the side toward the vibrating column by a thin mem- 
brane. In the figure, three such " manometric" cham- 
bers are represented; one of them occupying the 
middle point of the tube, which (the tube being open 
at both ends) is the place of the node when the fun- 
damental note is sounded. The other two divide 
equally the two halves of the tube, and mark the 
points where the nodes are formed in sounding the 
octave. The jets being lighted, a violent agitation of 
the central flame takes place whenever the sound of 
the fundamental note is heard, while the other two 
flames are but slightly disturbed. But on striking 
the octave, the middle flame comes to rest, and the 
agitation is transferred to the other two. This will 
be understood by considering that, at the place of 
the node, the air is alternately condensed and rarified 
without any motion of translation. When the node 
is in the middle, there is some variation of density 
at the points where the other flames are placed, but 
not very much. When the nodes are formed at these 
Koenig's N?d al-point points themselves, however, they become the centres 
Manometric Flames, of the greatest changes of density, while in the mid- 
dle of the column the motion is vibratory, but the density remains unal- 
tered. If the flames are made very small, the sounding of the funda- 
mental note quite extinguishes the middle one, but leaves the others 
burning. On the other hand, the octave extinguishes the extreme flames 
without affecting the middle one. 

Mr. Koenig has also adapted this method to the visible illustration of 
the interference of sounds. It has long been known that if two organ 
pipes perfectly in unison be placed side by side and sounded at once, 
their united notes are sensibly less forcible than when they are placed 
at some distance from each other. The reason of this is. that they 
mutually influence each other to vibrate alternately : that is to say. con- 
densation takes place at the nodes of the one, at the same moments at 
which the opposite condition exists at those of the other. The sound- 
waves produced in the surrounding atmosphere by these two vibrating 
columns are therefore in condition to interfere, so that to a certain extent 
they neutralize each other. The visible demonstration of this state of 




EFFECTS OF VIBRATIONS UPON FLAMES. 



513 



things is furnished by attaching to the centers of the two tubes a pair 
of mauometric gas jets like those just described, and bringing the flames 
one directly under the other. This may be done by suitably bending 
the small gas tubes which communicate with the manometric chambers. 
On sounding the tubes both flames will be agitated, but direct obser- 
vation will not permit the phases of their varying brightness to be dis- 
tinguished. But if a plane mirror placed by the side of the jets be rap- 
idly revolved around a vertical axis, each of the apparently single flames 
will be resolved into a row of separate flames; and then the fact will 
be manifest that all the separate images in each row fall into the dark 
intervals between the images of the other row. The appearance pre- 
sented by these flames is shown in the annexed figure. When one of 

Fig. 104. 



i 

4 

i 



Manometric Flames — tubes in unison. 

the tubes sounds a harmonic of the other, the images arrange themselves 
in a manner analogous; but the relations of the flame-images become 
less apparent as the ratios of the concords are less simple. By employ- 
ing only one flame, however, and bringing it into connection with the 
manometric chambers of both tubes at the same time, a compound 
image is produced, in which the mutual influence of the vibrations 
makes itself manifest. The figure here given is a representation of the 

Fig. 105. 








Manometric Flames — the tonic and the major third. 

appearance presented when the tubes employed give the fundamental 
and the major third, having the harmonic relation of five to four. 

One of the most interesting of the instruments exhibited by Mr. 
Kcenig, was his " Clang- Analyser," an instrument designed to demon- 
strate visibly the presence of harmonic overtones in all musical notes. 
33 i A 



514 



PARIS UNIVERSAL EXPOSITION. 



This is composed of a series of resonators, eight in number, adapted to 
a series of tones beginning with. C°, or C below the treble clef, and 
embracing the octave, the twelfth, the fifteenth, the seventeenth, the 
nineteenth and the twenty-second. These resonators are arranged one 
above another, as shown in the figure, opening all in a common direc- 

Fig. 106. 




Kcenig's Clang-Analyser. 

tion. A caoutchouc tube from the opposite extremity of each is con- 
ducted to a separate manometric chamber, having a gas jet attached. 
The gas jets are all arranged in a straight line, and parallel to them a 
mirror (four mirrors, in fact, forming a quadrangular solid) is mounted 
upon an axis, round which it is made to revolve rapidly by means of a 
crank and gear- work. The use of this apparatus hardly requires to be 
explained. When a musical note is sounded while the mirror is in rev- 
olution, all the tones contained in the clang will be immediately detected 
by the breaking up of the corresponding flames ; while the absence of 
others will be equally demonstrated by the fact that their flames appear 
iu the mirror as continuous unbroken luminous bands. 

Besides the instruments above described. Mr. Keenig exhibited Helm- 
holtz's apparatus for demonstrating the different acoustic characters of 
the vowels as uttered by the human voice ; which he has shown to result 
from the unequal predominance of the over-tones in these several sounds. 



CHRONOGRAPHS UNIVERSAL VIBROSCOPE. 515 

He exhibited, likewise, one or two forms of chronograph, in which the 
measure of time is effected by the undulating curves traced in the man- 
ner already described upon a revolving cylinder, by means of a delicat e 
point carried by a diapason. In one of these chronographs the vibra- 
tion is kept up by electro-magnetism, as in the acoustic comparator of 
Lissajous described above ; and in another, by what may be called the 
sympathetic method, which may be thus explained. Two perfectly 
equal diapasons are fixed to a common iron support, one of them directed 
upward and the other downward. It is this last that carries the tracer. 
The upper diapason is mechanically excited by the hand or by a violin 
bow; and the other, in consequence of their perfect unison, takes up the 
vibration. As the first may be touched from time to time without inter- 
fering with the chronograph, it is easy, with a little attention, to main- 
tain the vibration for any period. 

In the array of apparatus exhibited by Mr. Kcenig were embraced, ot 
course, many instruments and appliances for acoustic illustration and 
investigation which have not been enumerated here, such as plates, rods, 
cords, tubes, &c, most of which are familiar. 

WESSELHOPT 7 S UNIVERSAL VIBROSCOPE. 

An instrument of some interest was exhibited by Mr. Wesselhoft, of 
Eiga, and called by him the "Universal Vibroscope." The design of 
this is to enable an observer to make direct observation of the motion of 
a vibrating body, whatever may be its nature, and under any cir- 
cumstances. It is founded upon the principle of the well- known optical 
toy called the phenakisticope ; that is to say, the essential part of the 
instrument is a rotating disk, perforated near the circumference with 
equidistant sight holes. Suppose, for instance, that an observer, with 
this disk before his eyes, directs his attention to a singing flame or a 
vibrating rod. If the duration of the vibration is just equal to the inter- 
val between the passages of the succesive sight holes before the eye, the 
aspect of the flame or of the rod will be unchanged. Thus, if the rod 
happen to be caught at the point of extreme flexure on one side of the 
mean position, it will appear to be a permanently bent rod. And if the 
flame should be on the point of extinction when first seen, it will seem 
to be a steadily faint flame. But such an exact coincidence of intervals 
could hardly occur. The object will therefore be seen at its successive 
reappearances, in as many successive conditions; and owing to the per- 
sistence of impressions upon the eye it will not have been consciously 
lost sight of at all. The vibration, therefore, which is really rapid, will 
appear to be a motion comparatively deliberate, and the form of the path 
may be easily inferred. As it is necessary that the rotation of the disk 
should be rapid, it should be made of light material. The instru- 
ment exhibited was constructed of aluminium blackened. Card board 
would answer equally well in many observations of this description. 
Some magnifying power is desirable. This is furnished by a small tel- 



516 



PARIS UNIVERSAL EXPOSITION. 



escope mounted on an independent stand, and brought close to the 
revolving disk on the side opposite to the observer's eye. 

This instrument may serve as a means of determining the rapidity of 
vibration of the body observed. To this end it should be provided with 
a contrivance for regulating the velocity of rotation according to circum- 
stances, and should have a register of its actual velocity during the 
time of observation. 

iy._HEAT. 



THER3IO:tfETEKS. 

The display of thermometers by several exhibitors was very fine. 

Fig 107. The most remarkable were those of Mr. Richard Danger, some 
of which command a large range of temperature and are beau- 
tifully graduated, the tube containing the fluid being divided 
on one side and enameled on the other to make the marks con- 
[ spicuous, and the whole being surrounded for protection by an 
enveloping tube sealed to it above the bulb, which remains ex- 
| posed. Among a number of the thermometers ot Mr. Danger 
were several in which the graduation is carried to tenths of a 
degree, the divisions still being so large as to be easily distin- 
guishable. These are unprotected. The exposition of Mr. Dan- 
ger embraced a variety of delicate articles in glass, remarkable 
for their beaut}'. Of these were particularly noticeable his grad- 
uated pipettes, with glass stop-cocks, of which the neatness and 
elegance are no less admirable than the skill of their execution. 
Messrs. R. & J. Beck, of London, presented also a beautiful 
display of thermometers. Some models in this exposition were 
designed with a view to increase the sensitiveness by making 
the surface of mercury exposed to the influence of the external 
heat very large in proportion to the mass. This is accomplished 
by substituting for the ordinary bulb a tube coiled in spiral 
form, either flat or elongated. The annexed figure, Fig. 107, 
illustrates the second form of this instrument, which, aside from 
its practical superiority, is very tasteful in appearance. 

Mr. Baudin, of Paris, exposed a series of thermometers in 
which the sensitive fluid employed is alcohol tinged with a variety 
of prismatic colors. There are ten of these in the series, the ob- 
ject being to afford means for observation of the comparative 
absorbent powers of different colors for radiant heat. When 
exposed side by side to a common radiant source, as for instance 
in the direct rays of the sun, these instruments all disagree: 
while, if removed from the light and placed in an apartment of 
uniform temperature, their indications presently return to exact 

coincidence. 

One of the most recently invented thermometric instruments, and one 



THERMOMETERS. 517 

as curious as it is likely to be useful, Casella's mercurial minimum ther- 
mometer, was uot exposed. This instrument, which is the invention of 
Mr. L. Casella, maker of scientific instruments to the British admiralty, 
is as yet the only serviceable mercurial minimum thermometer, and the 
only minimum thermometer of any kind which is not in practice liable to 
troublesome derangements. As the maximum thermometers in common 
use are mercurial thermometers also, there is the additional advantage 
resulting from the employment of this instrument that both extremes of 
temperature are registered under the same conditions. There is no steel 
or other solid index subject to become entangled in the mercury contained 
in the tube ; and the annoyance which, in the common minimum thermom- 
eter, so often arises from the sluggishness, evaporation, or breaking of the 
liquid column, is entirely avoided. The general form is shown in Fig. 

Fiar. 108. 



f 

Casella's Mercurial Minimum Thermometer. 

108 5 d being a tube with large bore, at the end of which a flat glass dia- 
phragm is formed by the abrupt junction of the small chamber a b, the 
inlet to which at b is larger than the bore of the indicating tube, The 
result of this is that, having set the thermometer, the contracting force 
of the mercury in cooling withdraws the fluid in the indicating stem 
only, while, on its expanding with heat, the long column does not move, 
the increased bulk of mercury finding an easier passage through the 
larger bore into the small pear-shaped chamber attached. 

In arranging the instrument for use it is to be placed in a horizontal 
position, with the back plate e suspended on a nail, and the lower part 
supported on a hook,/. The bulb end may now be raised or lowered, 
causing the mercury to flow slowly until the bent part d is full and the 
chamber a b quite empty. At this point the flow of mercury in the long 
stem of the tube is arrested by adhesion to the diaphragm &, and indi- 
cates the exact temperature of the bulb, or air, at the time. On an 
increase of heat the mercury will expand into the small chamber a b; 
and a return of cold will cause its recession from this chamber only, 
until it reaches the diaphragm b, to which it adheres. Any further 
diminution of heat withdraws the mercury down the bore to whatever 
degree the cold may attain, where it remains until further withdrawn 
by increased cold, or till reset for future observation. When out of use, 



518 PARIS UNIVERSAL EXPOSITION. 

or after transit, it may be that raising the bulb may not at first cause 
the mercury to flow from the small chamber as above; in such case a 
slight tap or jerk with the hand on the opposite end with the bulb up, 
will readily cause it to do so. 

This ingenious instrument has been tested in use by Sir Henry James, 
director of the ordnance survey of Great Britain, by Mr. Stewart, director 
of the observatory at Kew, by Dr. Thompson, vice-president of the Brit- 
ish Meteorological Society, and by many other distinguished observers, 
by all of whom it has been very highly commended. 

PYROMETERS. 

A trustworthy means of determining with accuracy the high tempera- 
tures of furnaces, or any elevated temperature exceeding that of boiling 
mercury, has not as yet, perhaps, been successfully secured. The earliest 
pyrometer which actually came into use was that of Wedge wood, invented 
about 1780. The principle on which this invention was founded is the 
well-known property of clay to contract under the action of heat. In 
form, the pyrometer of Wedgewood was extremely simple. It consisted 
merely of a gauge for measuring the dimensions of certain little clay 
cylinders before and after their subjection to the heat of the furnace. 
The test was in itself a very rude one, but the uncertainty of the indica- 
tions of the instrument was increased by the fact, subsequently dis- 
covered, that clay may contract under the influence of a comparatively 
low temperature, long continued, to as great a degree as under a higher 
of less duration. 

It was proposed, at about the same time with the origination of 
Wedgewood's invention, to construct a thermometer for high tempera- 
tures on the plan of the mercurial thermometer, employing a fusible 
alloy instead of mercury, and a tube of clay enamel, or translucent porce- 
lain, instead of glass. This was the conception of Achard, and it has 
a prima facie plausibility in its favor; but it is not known to have been 
reduced to practice. In fact, considering the liability of the porcelain 
to contract in the furnace — the property from which the pyrometer of 
Wedgewood derives all that it has of practical utility — the indications 
of the high-temperature thermometer here proposed would be liable to 
uncertainty in a very high degree. Several very distinguished physi- 
cists have endeavored to reach a more satisfactory solution of this dim- 
cult practical problem by availing themselves of the expansibility of 
air under high temperatures. These efforts have been to a certain degree 
successful; but the methods to which they have conducted depend for 
their accuracy upon the truth of the assumption, not yetfully established. 
that the expansibility of gases at the highest artificial temperatures fol- 
lows the same law as at those at which this law has been experimentally 
verified. 

One of the most promising methods of pyrometric measurement which 
has yet been proposed is the suggestion of Professor Edmond Beeqiierel. 
of Geneva, and is founded on the principles of thermo-electricity. In 



PYROMETERS OPTICAL APPARATUS. 519 

the Exposition of 1867, Mr. Buhmkorff, of Paris, exhibits a thermo-electric 
pyrometer constructed under the direction of Professor Becquerel, which, 
in the experimental trials to Avhich it has been subjected, has furnished 
indications remarkably consistent with each other; while it is free from 
complication of parts and apparently capable of being made practically 
available for all the uses for which such an instrument is needed. The 
thermo-electric combination employed by Mr. Becquerel is a single couple 
formed of two equal wires of platinum and palladium, each being one 
millimeter in diameter and two meters in length, united by one extrem- 
ity in a junction formed by binding them firmly together with a fine 
platinum wire. The two elements, which are placed parallel to each 
other, are in contact to the extent of about one centimeter at the junc- 
tion. In order to keep them separate for the rest of their length, the 
palladium wire is passed through a tube of porcelain; and this tube, 
with the two wires, is subsequently introduced into a larger tube of the 
same material, which last is to be exposed to the heat of the furnace. 
Both tubes are then filled with sand. The two wires are suitably con- 
nected at their outer extremities with the binding screws of a Weber's 
galvanometer, which indicates electric intensities with great exactness. 
A scale of temperatures related to the intensities of the developed cur- 
rents has been prepared by Mr. Becquerel, by comparing the indications 
of an air pyrometer with those of the electric pyrometer when both are 
similarly exposed side by side. The divisions of this scale are equiva- 
lent to ten degrees centigrade each. 

It cannot yet be said, perhaps, of any form of pyrometer, unless of 
that of Wedgewood, which, as we have seen, is untrustworthy, and 
which at best indicates differences of temperature very imperfectly, that 
its use for practical purposes is entirely unattended with inconvenience ; 
but the electric pyrometer of Mr. Becquerel seems to come as near to 
fulfilling this condition as any that has yet been suggested. 

Y.— LIGHT. 

If the exposition in the department of optics were to be judged by the 
degree to which it gave evidence of recent progress in scientific discov- 
ery, there would be some reason to feel disappointment with the results. 
Since the invention of the spectroscope no new optical instrument has 
made its appearance designed as an aid to investigation in any field en- 
tirely new. Ou the other hand, the variety and beauty of the familiar op- 
tical instruments exhibited, their superior and often exquisite workman- 
ship, and the numerous improvements, mauy of them of importance, which 
were apparent in the details of their construction, gave to the exhibition 
an interest which, to some degree, compensated for the lack of novelty, 
and could not fail to impress the observer with a very high admiration 
of the accurate scientific knowledge and marvellous skill of their accom- 
plished constructors. In this field France presented by far the most 
brilliant display. England would have been placed next in rank by one 



520 PARIS UNIVERSAL EXPOSITION. 

who judged only according to the impressions produced upon the eye. 
A critical inquirer would, however, doubtless have pronounced that sub- 
stantial merit was not distributed in proportion to the number or splen- 
dor of the objects exhibited; and such a critic would have found much 
to admire in the less showy but by no means less interesting exhibitions 
of Switzerland, Bavaria, Prussia, and Austria. The United States were 
among the nations least conspicuous in this competition, only one or 
two of our accomplished opticians having entered the field at all, and 
they in a form so modest that their contributions probably escaped the 
general eye. 

OPTICAL OLASS. 

To a person unacquainted with the peculiar difficulties which have 
impeded the progress of improvement of optical instruments of the high- 
est order, it usually occasions some surprise to be told that the most 
serious of all these has always been the imperfection of glass. This sub- 
stance is one which is so far from betraying to ordinary observation the 
faults which make it useless to the optician, that the specimens which 
seem most brilliant are not seldom those which are in this respect most 
faulty. Two kinds of glass, crown and flint glass, are combined in the 
construction of achromatic lenses. Crown glass is a compound of silex, 
potash, and lime. In the composition of flint glass one important con- 
stituent is the oxide of lead. Flint-glass is not so much a double silicate 
of alkali and lead as a mechanical mixture of two silicates. The 
unequal density of these two substances prevents their formiug, while in 
a state of fusion, a mass of uniform character. The heavier of the two 
tends to sink to the bottom of the crucible, and the result is to produce 
a compound of very unequally refracting power. In the year 1824, a 
committee of the Eoyal Society of London, consisting of Mr. Faraday. 
Sir John Herschel, and Mr. George Dollond, was appointed to Conduct 
an experimental iuquiry into the processes of this manufacture, with a 
view to devise means of overcoming the difficulty here spoken of. The 
results of this investigation were communicated to the society by Mr. 
Faraday in 1829 ; but, though in many respects interesting, they served 
very little to advance the practical object in view. At this period the 
largest telescopic objective of satisfactory performance which the English 
opticians found it in their power to produce, did not exceed some five or 
six inches in diameter. A simple melter in a glass manufactory at 
Soleure, in Switzerland, by name Guinand, had previously to this, 
demonstrated the possibility of exceeding these moderate dimensions : 
but he made a secret of his process, and died iu 1823 without having 
disclosed it. He became, however, early associated with the celebrated 
Fraunhofer, and for some years furnished the material for the objectives 
which made the establishment of Ftschneider and Beichenbaeh at 
Munich so deservedly renowned. Though his method of proceeding was 
never published by himself, it continued to be practiced by his son, and 



OPTICAL GLASS. 521 

it is still pursued by Mr. Fell, of Paris, a lineal descendant of G-uinand, 
who presented in the Exposition of 18G7 the most brilliant display of 
optical glasses which appeared there from any country. The nature of 
the process of manufacture is now substantially known. It consists in 
uniting numerous small selected masses of glass of ascertained equality 
of density and uniformity of refracting power, into one large mass, by 
pressure while in a plastic condition. It is a process therefore analogous 
to that of the welding of iron. 

Among the objects exhibited by Mr. Feil were several specimens of 
the silico-borate of lead, a kind of glass of great specific gravity which 
was first produced by Faraday in the course of the investigation above 
mentioned, and which was obtained by him with a mean refracting index 
as high as 1.8735. He gave it the name of " heavy glass," its specific 
gravity varying from 4.20 to 5.44. The refracting index of the specimens 
exhibited by Mr. Feil was somewhat less than that above stated, being 
only 1.727. Mr. Feil also exhibited a magnificent disk of flint-glass of a 
diameter of seventy-two centimetres, or over twenty-eight inches. 

Very large disks were also exhibited by Messrs. Chance, of Birming- 
ham, England, a firm which has been long distinguished for the excel- 
lence and the large dimensions of its optical glasses. In 1855 this estab- 
lishment exhibited in the Exposition of that year a pair of disks, crown 
and flint, about an inch larger than that of Mr. Feil above mentioned. 
These were purchased for the observatory of Paris, but they have not 
as yet been mounted. Messrs. Chance exhibited also a magnificent 
Fresnel light-house lens, formed in rings or zones of grand dimensions. 

The exposition of Merz, the celebrated constructor of astronomical 
instruments of Munich, embraced one object-glass seventeen inches in 
diameter, and another of ten inches. 

Very beautiful un wrought specimens were exhibited by Daguet, of 
Switzerland, with polished facets serving to show their excellence of 
quality. 

Besides these, Steinheil of Munich, Secretan of Paris, Voigtlander of 
Vienna, and others, exhibited object glasses less remarkable in size, but 
of very superior quality. 

The great glass company of St. Gobain, Chauny and Cirey, ought not 
here to be overlooked, though they exhibited nothing in the class 
embracing optical instruments. This company manufactures glass plates 
upon the grandest scale. One of their plates exhibited was found, by 
actual measurement, to have the dimensions of nineteen feet and six 
inches by eleven feet. They exhibited also very fine disks designed for 
the mirrors of reflecting telescopes. 

A very fine collection of plane glasses with parallel surfaces was exhib- 
ited by Messrs. Radiguet and Son of Paris. The sizes ranged from one 
inch to more than twelve inches square. There were also circular glasses 
of similar dimensions. Many of these glasses were colored, to serve as 
darkening glasses for reflecting instruments, or for purposes of experi- 
mental investigation. 



522 PARIS UNIVERSAL EXPOSITION. 

The exhibition of prisms by many distinguished constructors was very 
beautiful. Very large right-angled prisms (four inches on a side) were 
shown by Hoffman of Paris, who also exhibited admirable prisms of rock 
crystal, suitable for the study of the fluorescent rays beyond the violet. 

The prisms of Steinheil, of Munich, were remarkable for the perfection 
of their angles. The hollow prisms for experiments on transparent 
fluids by this constructor were formed of plates of plane glass united 
without cement, being made water-tight by the perfection and polish of 
their surfaces. 

A collection of thirty-five equal and similar prisms formed of different 
materials, which had been employed in the investigations of Bailie on 
refraction, was exhibited by Madame Bertaud, of Paris, who also exhib- 
ited Silbermann's prism of variable angle for fluids, intended to facilitate 
the illustration of the laws of refraction in presence of large assemblies. 
The axis of this prism is horizontal. The ray of light to be experimented 
on is thrown vertically downward, and the refracting angle is that which 
is formed between the surface of the contained liquid and one of the 
inclined sides. By turning the prism around a horizontal axis of motion, 
the refracting angle is varied at pleasure, since the upper surface always 
remains horizontal. This construction facilitates the illustration of the 
variation of refractive power with density, which is accomplished by 
introducing into the liquid, during the progress of the experiment, various 
soluble salts. 

TOPLER'S STRES: DETECTOR. 

In connection with this cursory notice of the optical glasses exhibited 
in the Exposition, it is proper to mention an ingenious apparatus invented 
by Professor Topler, of Riga, (Russia,) and exposed by Mr. TTesselhoft, for 
detecting the faults of such glasses when they arise from irregularities 
of density. Such faults are in the nature of stria?, or transparent streaks. 
and are sometimes so gross as to be immediately perceptible by the 
unaided eye. But even when they are sufficiently slight to escape detec- 
tion by any ordinary or simple method of observation, they are often 
still serious enough to render the glass in which they occur unfit for the 
more important uses of optics, as, for instance, for the construction of 
telescopes. 

The apparatus of Professor Topler embraces, first, a source of light, 
which is furnished by a lamp having before it an opaque disk provided 
with apertures of different dimensions which can be successively 
brought in front of the blaze, thus enabling the observer to vary the 
size of the radiant at pleasure. The light of this source falls upon a 
large lens of short focus, which produces a luminous image of it on the 
opposite side. If the observer place his eye immediately behind this 
image, he will see the lens uniformly illuminated. In this state of things 
a small opaque disk introduced exactly at the focal point and equal to 
the focal image, will eclipse the lens entirely. But this eclipse will nor 



topler's stride APPARATUS POLARIZATION. 523 

completely take place unless the lens is free from all imperfections pro- 
ducing irregular refraction. If such irregularities exist, they will cause 
certain rays to deviate from the focal point in which the light is chiefly 
concentrated, and will produce an image of their figure, apparently 
traced more or less brightly upon a dark ground. The observation is 
facilitated by employing a telescope to assist the eye. 

Topler s strise apparatus may, therefore, be described as being made up 
of the luminous source, the condensing lens, and the telescope. This last 
is called the analyzer. A large photographic lens of good quality serves 
very well for the condenser. This must be without imperfections of its 
own. Then, if an object glass, designed for a telescope or other pur- 
pose, is to be examined, it is placed, in general, as near as possible to 
the condenser, and on the side of the analyzer. The two lenses thus 
combined may be regarded as practically forming one. To the analyzer 
is attached the eclipsing apparatus, which is interposed after the adjust- 
ments are completed. The occurrence of a complete eclipse will be 
evidence of the good character of the glass under observation. The 
delicacy of this apparatus is such that Professor Topler has successfully 
employed it in investigating the influence exercised upon the refracting 
power of solid bodies by pressure, or by variations of temperature ; and 
in the atmosphere, by sound waves and other disturbing causes. 

POLARIZATION. 

While in the apparatus for experiment and research on the double 
refraction and polarization of light, many things were exhibited which 
were at once very interesting and very beautiful, there was scarcely 
anything present which could be said to mark decided progress in recent 
years. The exposition of doubly refracting crystals, cut for the display 
of their characteristic systems of colored rings and fringes, was very 
full and admirable. This was especially true of the collection of Hoff- 
mann, of Paris, who, in this speciality, is without a rival. Dnboscq, 
Bertaud, and Soleil also exhibited a great variety of interesting objects 
and articles of apparatus belonging to this department of optics. Mr. 
Soleil is the son of the highly distinguished optician and physicist, 
whose labors early contributed so much to the advancement of prac- 
tical investigation in the higher optics, and who originated the very 
ingenious saccharimeter which bears his name. The son, who inherits 
much of his father's ability, has recently laid before the Academy of 
Sciences a description of an original method of obtaining plates of rock 
crystal with planes parallel to the axis, or of determining the error of 
parallelism, which was rewarded by that body with an expression of 
their high approbation. Mr. Soleil presented plates illustrative of his 
method, and enabled the jury to test the character and value of the 
indications by means of which his determinations are made. 

HOFFMANN'S POLARIZATION MICROSCOPE. 

In the collection of Hoffmann was embraced a large variety of tour- 



524 PARIS UNIVERSAL EXPOSITION. 

malines of all sizes and colors. By the happy combination of these, he 
succeeds in obtaining polarized light very nearly or qnite colorless ; and he 
thus, in some of his instruments for investigation, has been able to sub- 
stitute tourmalines instead of calcite prisms, with the advantage of a 
largely increased field of vie w. He exhi bited, for instance, a polarization 
microscope, designed to show the colored rings seen in doubly refracting 
crystals cut across the axis, which for this purpose is superior to any 
polariscope or other combination of apparatus heretofore constructed. 
The instrument is at the same time very much more compact than the 
arrangements of Biot, Amici, Xorremberg, or any others. These advan- 
tages are secured by employing an achromatized tourmaline as the 
polarizer. The inconveniences of polarization by reflection are thus 
avoided, and it becomes possible to observe with artificial light as well 
as with the natural. The parts of this microscope are, first, a concave 
mirror for collecting light, made of glass coated with platinum by Dode's 
process — this metal being j)referred to silver on account of its inalter- 
ability; secondly, a combination of four lenses forming the object- 
ive; thirdly, a combination of three lenses forming the ocular; and 
fourthly, a Nicol's prism as an analyzer, with a divided circle. The 
crystal to be examined is supported on the stage in a manner which 
permits a free motion of revolution, and also a change of position lat- 
erally. A number of accessories accompany the instrument, and add to 
its usefulness. There are, for instance, mono-chroinatic glasses, by the 
interposition of which the rings or fringes observed will be exhibited 
with increased sharpness of definition, and in greater uuinber; also 
mica plates of half or quarter of a wave value, quartz plates cut parallel 
and perpendicular to the axis, &c, &c, to be used in studying the dis- 
position of the colors, the positive or negative character of the crystal, 
the direction of rotatory polarization, and other interesting properties. 
The instrument is further furnished with a provision for revolving the 
analyzer and polarizer at the same time, to demonstrate that while the 
curves or lemniscates of biaxial crystals revolve, the line which joins the 
centers of the two systems of rings preserves its position. The field of 
view of this instrument is so large that it shows not only both systems 
of rings in topaz, which in this crystal are separated one hundred and 
twenty-one degrees, but also even those of hyposulphite of soda, which are 
the most widely separated of any known. When applied to the measure- 
ments of angles exceeding one hundred and thirty-five degrees, the crys- 
tal under observation is immersed in a bath of oil, (olive oil bleached in 
the sunlight,) sulphide of carbon, or other highly refracting liquid. The 
trough should be made of thin glass, and should have a plane bottom of 
uniform thickness. The ciwstal is held in the liquid in a pair of tweezers. 
It is a great recommendation of this instrument that it admits of easy 
transformation into an ordinary polariscope, and is adapted to a larger 
variety of applications than any instrument of its class hitherto con- 
structed. 



POLARIZATION — Hoffmann's saccharimeter. 525 

THE HOFFMANN-WILD SACCHARIMETER. 

Another interesting instrument exhibited by Mr. Hoffmann is the sac- 
charimeter or " polaristrobometer," of which the original idea was sug- 
gested by Professor Wild, of Berne. This instrument, besides possessing 
great sensibility, is very sharp in its indications. The indicator is a polar- 
iscope of Savart,. formed of two plates of quartz cut oblique to the axis 
and crossed upon each other, which exhibit parallel friuges with a central 
band, white or black, according as the polarizer and analyzer are co- 
incident or crossed. The polarizer and analyzer in this instrument are 
both Mcol's prisms. The analyzing prism, which has a motion of rota- 
tion, is furnished with a divided circle. The observation is made by 
means of a small telescope, in which are stretched cross-lines inclined 
forty-five degrees to the vertical in the field of view. Between the indi- 
cator and the polarizer is placed the tube containing the solution to 
be observed. 

The mode of observation is as follows: First, for adjustment. In the 
day time, the instrument may be directed towards a white cloud, or 
towards a white wall or screen. At night, it may be turned directly 
toward a lamp. It is desirable to bring the polarizer and analyzer into 
such a position, relatively, that the field of view may present a white 
stripe upon the center of the cross, bordered by two dark stripes. This 
adjustment having been made, it is to be noticed what is the index 
error; and as the analyzer is capable of being turned round in its circle, 
it is turned by the amount of the error, so that when the zero of the 
circle is brought to the fixed index, the appearance just described may 
be present. The tube containing the liquid to be examined is then intro- 
duced ; and this, if possessing the property of rotatory polarization, will 
turn the plane of polarization of the incident light to the right or the left, 
so as to extinguish the white band in the middle of the field, and cause it to 
be replaced by one more or less dark, and bordered by colored fringes. 
A corresponding rotation of the analyzer will restore the central white 
band, and the number of degrees necessary for this restoration will be 
read off on the circle. The direction in which it has been necessary to 
turn the analyzer will determine whether the rotatory power of the liquid 
is positive or negative. It is stated that the instrument is accurate to the 
tenth of a degree, at least for angular movements below five degrees. 
For larger rotations a severer accuracy will be obtained by employing 
mono-chromatic light; as, for instance, the soda flame obtained by burn- 
ing an alcoholic solution of salt. Practically the same result may be 
obtained in compound light by interposing between the eye and the 
analyzer a disk of red glass. 

THE HARTNACK-PRAZMOWSKI POLARIZATION PRISM. 

While speaking of the exposition of matters relating to polarization, 
the new calcite polarization prism of Hartnack and Prazmowski ought 
not to be overlooked. This prism, introduced by Hartnack for use in 



526 PARIS UNIVERSAL EXPOSITION. 

his microscopes, but capable equally of general application, is constructed, 
like the prism of Nicol, on the principle of suppressing the ordinary ray 
by internal reflection. In the prism of Mcol there is first formed an 
oblique rhombic prism, with lateral edges exceeding the terminal as 
three to one, by dividing the original crystal according to its natural 
cleavages. A diagonal section is then made of this prism, in such a 
manner as to divide it symmetrically, from one of the obtuse angles to 
the other ; and the separated segments are re-united by a cement of 
Canada balsam. In the Hartnack-Prazmowski prism, after the original 
crystal has been prepared as above, only with lateral dimensions propor- 
tionally greater by rather more than one-third, the ends are truncated 
by planes inclined about twenty-eight degrees to the optic axis, and on 
these planes as bases is constructed a rectangular prism, which is after- 
ward sawn asunder in a diagonal section conjugate to the optic axis, or 
coincident with what may be called the optic equator. This construc- 
tion increases the field of view about one-third — a very sensible advan- 
tage to the observer, especially in microscopic observation ; but it cuts 
the natural crystal to a greater disadvantage than the method of Mcol, 
In re-uniting the sundered portions of the prism, Mr. Hartnack uses 
drying oil (linseed) as a cement, by preference to Canada balsam ; the 
index of refraction for this oil corresponding very closely with that of 
the extraordinary ray. In regard to the absolute ultimate relations of 
length and breadth in this prism and in that of Mcol there is no mate- 
rial difference ; but the rectangular form is a great advantage. 

The most compact form of calcite polarization prism by far is that of 
Foucault, n which the separated segments, after being polished on the 
surfaces of the section, are re-united without a cement, a film of air only 
intervening between the surfaces in juxtaposition. Unfortunately, the 
ordinary ray is not totally reflected by this prism, unless the rajs of the 
incident beam are parallel. When used with divergent or convergent 
rays its performance is very imperfect, and it is therefore not adapted 
to the uses of the microscope. 

MISCELLANEOUS APPARATUS. 

The apparatus devised by Mr. Jamin for measuring the difference of 
phase between the undulations of two rays was exhibited by the house 
of Madame Bertaud in a style of elegance amounting to luxury. The 
same house also exhibited the elaborately constructed instrument by 
means of which Mr. Cornu has conducted his interesting investigations 
of the reflection of crystalline surfaces. 

The exposition of Mr. Soleil embraced also Fizeau's apparatus for 
measuring the expansion of crystals in different directions under the 
influence of heat. The crystal, reduced to the form of a plate with par- 
allel surfaces, rests upon the curved surface of a plano-convex lens of 
glass having a large radius of curvature, and presents to the observer 
who views the point of contact from above, the colored rings of Newton, 
As the crystal expands, these rings undergo apparent changes of diame- 



PHOSPHORESCENT POWDERS — SPECTROSCOPES. 527 

ter, and the measurement of these changes which the apparatus is 
designed to effect furnishes the data for deducing the law of relative 
expansion. 

PHOSPHORESCENCE. 

Preparations of phosphorescent material, which, on being viewed in 
darkness after a brief exposure to the sun, appear brilliantly luminous 
and exhibit the most superb tints, have been in recent years very con- 
siderably multiplied. These were beautifully illustrated in the exposi- 
tions of Alvergniat Brothers, Mr. L. A. Gaiffe, and perhaps others. The 
simplest form in which the preparations are displayed is to introduce 
them into glass tubes, which are afterwards hermetically sealed. A 
series of such tubes is arranged side by side in a dark box. After expos- 
ure the box is carried into a dark room and opened, when there bursts 
forth a glow of varied and rich tints, which to a spectator unprepared for 
the surprise is truly dazzling. These phosphorescent powders were, how- 
ever, managed by the ingenious exhibitors so as to produce effects still 
more striking than this. Upon a dead-black surface they had been 
spread out in thin layers, so as to form images of familiar objects in their 
natural, but more than naturally brilliant, colors. A thin coating of 
paraflme secures their adhesion, without in any manner injuring their 
phosphorescent properties. Butterflies, ornamental stars, and other fan- 
ciful images were thus prepared, the powders being laid on according to 
the tints they are capable of producing, as a painter lays his colors upon 
a picture. Before exposure to the sun the whole image is of a dull and 
uninteresting uniformity of gray-white tint, but the first touch of the 
sun's rays kindles it into beauty. One of the most striking objects of 
this class exhibited by Mr. Gaiffe was a representation of the solar spec- 
trum. The spectator could hardly persuade himself that it was not the 
real object. 

SPECTROSCOPES. 

The principal exhibitor of spectroscopes was Mr. Duboscq, of Paris. 
This exhibitor presented a variety of models, with prisms varying in 
number from one to six. The six-piisni spectroscope of Mr. Duboscq is 
so constructed as to permit the use of all the prisms at once, or of one 
or two only; the observing telescope meantime retaining its place. The 
telescope receives two motions of adjustment, one vertical and the other 
horizontal; and also a lateral micrometric movement for ranging along 
the spectrum. The same exhibitor showed also the pocket spectroscope 
of Amici, in which the light, after refraction by a single prisin, is brought 
back to the direction of incidence, without"" being affected as it respects 
dispersion, by total interior reflection from one of the surfaces of a sec- 
ond prism of suitable form. A spectroscope exhibited by Brunner, on 
the plan of Jamin, capable of being used also as a goniometer, and hav- 
ing a divided circle of twelve inches in diameter, was one of the finest 
instruments of its class in the Exposition. 



528 PARIS UNIVERSAL EXPOSITION. 

The most convenient form of spectroscope for ordinary nses is the 
direct- vision spectroscope, in which the dispersion is effected by prisms 
contained within the tube of the observing telescope itself, as in the case 
of Amici's pocket spectroscope mentioned above. The Abbe Moigno, 
in his journal Les Mondes, states that Jansen was the first to design a 
spectroscope in this form, which seems not to have essentially differed 
in principle from that of Amici, but which was considerably more pow- 
erful. In the instrument of Amici the ray, after having been dispersed 
by one prism, is brought by reflection into its original direction, the dis- 
persion remaining. In Jansen's, a second pair of prisms is placed imme- 
diately behind the first, which is in all respects similar to that. The 
effect is therefore to double the dispersion. 

A form of the instrument superior to either of these has been con- 
trived by Hoffmann, of Paris, the very able constructor to whose skill the 
investigators of the higher optics have been so much indebted, and who 
has furnished to Father Secchi and to Mr. Huggins the instruments 
which have enabled them to prosecute so successfully the spectral analy- 
sis of stellar and nebular light. In Mr. Hoffmann's direct-vision spec- 
troscope, the apparatus for dispersion consists of five prisms, three 
of crown glass and two of flint glass, cemented together into one system 
with their refracting angles alternately in opposite directions. The 
arrangement resembles that of the group of letters AVAYA, in which 
the cross-line of the letters A indicates the path of the light through 
the system. The dispersion is differential, the angles of the prisms 
being so chosen as to compensate the mean refraction; and the mean 
ray emerges parallel to the direction of incidence. But as the extreme 
rays of the spectrum produced by the dispersion are necessarily not 
parallel to the same direction, the tube is jointed at a point just behind 
the system of prisms, and the part near the eye has a liberty of lateral 
motion sufficient to enable the observer to bring any portion of the spec- 
trum into the field of visiou. The angles actually given to the several 
prisms at their summits are ninety degrees for the two flint-glass prisms, 
represented in the group of letters above by the two Y's, and also for 
the central prism of crown glass. The angles of the extreme crown- 
glass prisms are only sixty-nine degrees. 

It is obvious that by increasing the number of prisms a larger disper- 
sion might be obtained; but this would render the instrument more 
cumbrous, and would diminish the intensity of the illumination. The 
system of prisms occupies of course a position in the tube immediately 
in front of the objective of the telescope. But in front of the system 
itself is another lens designed to render the rays parallel as they fall on 
the prisms; and the tube, which is extended beyond this lens, carries at 
its extremity the variable aperture through which the narrow beam of 
light to be observed is admitted. In order to compare this light with 
that coming from a different source, a small reflecting prism is placed in 
front of the opening which it covers only in part, and which is sustained 
by a support fastened to the tube by a ring clamp. A micrometer very 



ASTRONOMICAL PHOTOGRAPHS TELESCOPES. 529 

finely divided on glass is introduced into the field of view within the 
instrument, by means of which the observer may measure the distances 
between the spectral lines. 

Before leaving the subject of the spectroscope, mention must be made 
of the extended and beautifully clear photograph of the spectrum exhib- 
ited in the United States section by Mr. Lewis M. Eutherfurd, of New 
York, which excited great interest and attracted very general admira- 
tion. It was the only object of its kind in the Exposition. 

The same gentleman also exhibited a photographic view of the moon 
on a very large scale, (twenty-one inches in diameter,) which for sharpness 
of delineation of the features of that remarkable body, may justly be 
pronounced the very best representation of the object which has yet 
been obtained. In making this remark the admirable photographs of 
the same body by Dr. Henry Draper, of New York city, and by Mr. 
Warren De la Eue, of London, are not forgotten. These very beautiful 
objects, for which a silver medal was awarded to Mr. Eutherfurd, have 
been presented by him to the Conservatoire des Arts et Metiers, of Paris. 

TELESCOPES. 

Mention has already been made of the telescopic objectives sent to 
the Exposition by many distinguished constructors. The number of tel- 
escopes of large dimensions present, fully mounted for use, was not 
large. It was hardly to be expected that it should be, considering the 
costliness of these instruments and the risk attending their transporta- 
tion to distances. The most beautiful object of this kind was an equa- 
torial by Dallmeyer, of London. This also presented some novelties in 
the details of its mounting. The instrument is provided with two inde- 
pendent hour circles, driven by the same mechanism, one of which gives 
the right ascension of the object observed, and the other, which is under 
the eye of the observer, the sidereal time. Adjustment in right ascen- 
sion can be effected, to a certain extent, without interfering with the 
action of the driving power, by a movement of the tangent screw in the 
direction of its length. 

In the Eussian section, Mr. G. Brauer, of St. Petersburg, exhibited a 
transit instrument in which the eye piece is situated in the axis of rota- 
tion. A reflecting prism placed in the middle point of this axis receives 
the light from the objective and deflects it at right angles to its original 
direction. The advantage of this arrangement consists in the fact that 
the position of the observer remains unchanged, whatever be the posi- 
tion of the telescope, and that he looks always in a horizontal, that is to 
say, a convenient, direction. Whether there may not be some compen- 
sating disadvantages, remains to be tested. 

Astronomical telescopes of merit were exhibited by Mr. P. G. Bardou, 
and Mr. N. E. Evrard, of Paris, each of these having a clear aperture of 
ten inches in diameter. Mr. Bardou presented, in addition to this, a 
truly splendid collection of terrestrial telescopes of very various sizes, 
and different styles of mounting. Many of the larger forms were mounted 
34 i A 



530 PARIS UNIVERSAL EXPOSITION. 

in aluminium, with the advantage of great reduction in weight. Obser- 
vation with these instruments is attended with greatly diminished 
fatigue, when they are compared with others mounted as usual in brass. 

A rather curious telescopic instrument was exhibited by Mr. H. Aus- 
feld, in the Prussian section, called Zollner's Astrophotometer, a name 
which explains itself. The design is to measure the brightness of the 
stars by comparing them with an artificial star of standard brightness. 
The telescope is directed to the natural star, and the light of the arti- 
ficial star is introduced through a lateral tube. A petroleum lamp serves 
for this object, the lateral tube carrying a diaphragm with a minute 
perforation in the center. In the interior of the principal tube, a plane 
glass mirror with parallel surfaces, placed at an angle of forty -five 
degrees, reflects the light of the artificial star to the eye; and as the 
mirror has a sensible thickness, two images are perceived with a small 
space intervening between them. The image of the natural star is 
brought to occupy this intermediate space. The lateral tube contains a 
polarization apparatus, by means of which the light of the artificial star 
may be modified both for color and for brilliancy. The first adjustment 
is for color. By rotating the polarization system the tint which corres- 
ponds to that of the real star observed is easily obtained, as in the 
saccharimeter. Then by turning one of the prisms of the system, the 
brightness of the artificial star, which is always at first superior to that 
of the real object, is gradually subdued until the two intensities are 
sensibly equal. As the image reflected from the first surface of the 
mirror is necessarily the brighter of the two, this one is selected as 
the standard of comparison. The other serves as a lower limit, and 
between the two the determination can be very accurately made. 

A compact pocket telescope was exhibited by Mr. Hoffman, which 
seems to be very well adapted to the uses of army officers, explorers, and 
travelers, being without a draw ; and yet, though only five or six inches 
in actual length, having a real focal length nearly three times as great. 
This paradoxical effect is produced by the introduction into the body of 
the instrument of two equilateral right-angled glass prisms, by means of 
which the light of the objective is made to traverse a space nearly three 
times the length of the instrument, in passing from the objective to the 
ocular. One of these prisnis, at the end next the observer, receives 
the light from the objective perpendicularly upon the hypothenuse, and. 
by two successive internal and total reflections, sends it back toward 
the object. The second prism receives in like manner the returning 
rays, and, by a second similar double reflection, sends them back once 
more in their original direction to the eye. This telescope, as the Abbe 
Moigno asserts, was selected by the Emperor on the eve of the campaign 
of 1856, in Italy, for his personal use; and "was made the inseparable 
companion of his glorious expedition." 

Opera and marine glasses were exhibited in large numbers, by many 
constructors. Among instruments of this description, was one designed 



TELESCOPES — FOUCAULt's REGULATOR. 531 

for the pocket, by Mr. A. Bieder, of Paris, in which the lenses were 
hinged in snch a manner as to fold down flat. In this form the instru- 
ment is very convenient for travelers or sight-seekers, to whom, in its 
ordinary form, it is often an incumbrance. It appeared to be well con- 
structed, and not liable to derangement. 

Among the accessories to the telescope deserving notice in the Expo- 
sition, may be mentioned the substitutes for the spider lines of micro- 
meters, exhibited by Breithaupt & Son, of Hesse-Cassel. These con- 
structors employ for this purpose lines ruled with a diamond point, on 
plates of thin glass. There is no objection to such micrometers, unless 
it be the loss of light occasioned by the introduction of additional 
reflecting surfaces; while the advantage resulting from their inaltera- 
bility of position is very great. Spider lines may become displaced, or 
they may be relaxed in consequence of the varying hygrometric state of 
the air ; while the plates, unless broken, an accident to which in their 
protected situation they are not liable, are subject to no sensible change. 
And even in case of a fracture, a reserve plate may be introduced with 
very trivial loss of time ; while the reconstruction of the spider-line 
micrometer is a troublesome task. 

The isochronal regulator of Foucault is another of these accessories, 
which is as admirable in its performance as useful in its results. This 
was illustrated in a striking piece of mechanism exhibited by Eichens, 
of Paris, and constructed by him as the driving apparatus of an equa- 
torial telescope designed for the observatory of Lima, in Peru. The 
resistance to acceleration in this contrivance is furnished by two wind- 
vanes attached to the outer angles of a jointed parallelogram, which is 
carried by a spindle forming the axis of the last wheel of the train. 
Between this variable fly and the driving weight, there is such a con- 
nection that each opposes the variation of the other so efficiently as to 
leave the resulting velocity strictly constant. The machine may be said, 
indeed, to be very slightly over-corrected ; for when the driving weight is 
largely varied, reduced, for example, by one-half, or increased by one- 
half, there is a trivial increase of velocity with the minimum weight. 
But for any fluctuations of resistance to motion likely to occur under 
the conditions in which the machine is to be used, the variation is prac- 
tically insensible. 

Reflecting telescopes were illustrated in the Exposition only by a single 
example. Mr. Secretan, of Paris, exhibited a telescope of this descrip- 
tion, with a silvered glass speculum ; but its dimensions were quite 
moderate, only slightly exceeding six inches in diameter. The same 
constructor has, however, produced other telescopes of the same kind 
of much larger dimensions ; one of which, constructed for the observa- 
tory of Marseilles, has a diameter exceeding two feet and a half. In our 
own country, we have a very fine example of such an instrument, in the 
silvered- glass reflecting telescope, constructed by Dr. Henry Draper, of 
New York, and described by him in the 14th volume of the Smithsonian 



532 PARIS UNIVERSAL EXPOSITION. 

Contributions to Knowledge. The substitution of silvered glass for 
speculum metal in this class of astronomical instruments was originally 
suggested by Mr. Foucault, and the resulting advantages are very great. 
The specific gravity of glass is two or three times less than that of metal ; 
and besides this, from its great rigidity, the same thickness is not 
required in a glass mirror which is indispensable in the heavier material. 
Glass is also much more easily wrought than metal ; and the loss of 
light from polished silver is but an inconsiderable fraction of the whole, 
while the loss from the surface of a metallic mirror is from one-third to 
one-half. And it is an important consideration that, if from any cause 
the silvered surface of the glass mirror should lose its brightness, the 
entire coating can be easily removed by solution and replaced by another, 
without the necessity of grinding anew. For these reasons it is prob- 
able that the reflecting telescope will hereafter come into more general 
favor than has been hitherto the case. 

^HOROSCOPES. 

In no branch of physical investigation has the number of zealous 
devotees in recent years more rapidly increased than in the study of 
microscopic organisms. And no instrument of optics has occupied in 
its construction a larger amount of practical skill of the highest order, 
or has received more numerous and more important improvements, 
whether in its optical or its mechanical parts, during the same time, 
than the microscope itself. It is, indeed, the high perfection and won- 
derful power of this instrument as at present constructed, which, by 
affording clear and satisfactory views of the structure of objects only 
recently esteemed excessively difficult and doubtful, and by thus 
immensely diminishing the labor of microscopical research, has given 
to it its present great and rapidly increasing popularity. 

The modern microscope may be said to date from the year 1829, the 
date of the publication by Mr. J. J. Lister of his well-known empiric- 
ally discovered laws governing the aberrations of lenses, and the prac- 
tical methods deduced from them of balancing these aberrations in a 
system of lenses against each other. The combinations of glasses, 
which had been previously most satisfactory in their performance, in 
the objectives of Chevalier and other eminent opticians, had been 
rather the result of patient experiment or happy accident, than of any 
antecedent calculation founded upon established principles. And the 
investigations of the earlier microscopic inquirers, such as Leeuwen- 
hoeck, Swammerdam and others, had been conducted almost wholly by 
means of single lenses. In the time of these distinguished investi- 
gators, indeed, the compound microscope was esteemed, and not with- 
out reason, as comparatively untrustworthy ; and the difficulties under 
which they prosecuted their researches were so great, as to make the 
recorded results they left behind them seem, at the present day. for their 
general accuracy, to have been almost miraculous achievements. 



MICROSCOPES, EXALTATION OF RESOLVING POWER. 533 

The effect of tlie introduction of Mr. Lister's improvements was imme- 
diately to throw nearly the whole class of what had been called test 
objects, into the category of common objects ; but it created a new set of 
tests, or a new succession of tests, of constantly increasing difficulty ; 
and in the active rivalry which has grown up between the many accom- 
plished opticians of recent years who have devoted themselves to the 
improvement of this instrument, the chief contest has been, which 
should most satisfactorily resolve the most difficult of these tests. The 
tests themselves here spoken of are, in general, certain exceedingly 
fine markings which exist upon the minuter natural objects. For the 
more important uses of the microscope, the resolution of these mark- 
ings cannot be said to be essential ; but inasmuch as to resolve them 
implies in the microscope a power of definition carried to the last degree 
of perfection, the effect of this contest has been undoubtedly greatly to 
improve the instrument for all other purposes. For though the object- 
ives of highest resolving power are not those which are most service- 
able for the ordinary uses of the botanist, the mineralogist, or the phys- 
iologist, they involve, nevertheless, all the difficulties of construction 
which attend the latter, and others besides, so that their improvement 
implies a corresponding improvement of the whole series. 

The expedients by which the resolving power of microscopic object- 
ives is exalted are principally two, the shortening of the virtual focal 
length of the system, and the enlargement of the angular aperture. By 
angular aperture is meant the angle formed at the front of the objective 
by lines drawn from its center in all directions, limiting the visibility of 
objects placed before it. This also is the angle of spread of the cone of 
rays proceeding from a given point in the object observed, which, fall- 
ing on the nearest lens, are so refracted as to meet the eye. 

The shortening of the focal distance has been progressively carried to 
a point at which nothing further can probably be done usefully in this 
direction. Messrs. Powell and Lealand, of London, whose absence from 
the Exposition was much regretted, have constructed objectives of great 
merit, having a virtual focal length of only one-fiftieth of an inch. Mr. 
Hartnack, of Paris, states the focal length of his highest number (No. 18) 
at less than half a millimeter, or one fifty-fifth of an inch. When it is con- 
sidered that this is not the distance at which the object must be placed 
from the front glass of the instrument, but that this latter distance is 
materially less, not exceeding the -^ or the -^-J-g- of an inch, and that 
the objects to be observed are of such delicacy as to require to be pro- 
tected by a covering of thin glass, it will be seen that the expedient 
here spoken of for improving the power of the instrument has been 
worked out to the last point of availability. 

The same remark is equally true of the other. The angular aperture 
of microscopic objectives has been increased up to one hundred and 
seventy-eight degrees ; but this increase, at least for the last fifteen or 
twenty degrees, is attended with no very perceptible gain of power, 



534 PARIS UNIVERSAL EXPOSITION. 

since the extreme rays meet the front of the objective so obliquely that 
they are principally reflected and lost. In order to obviate in some 
measure this disadvantage, some constructors have given to the front 
surface of the foremost lens of the system a slight concavity ; but the 
extent to which this modification can be carried is quite inadequate to 
afford any effectual remedy. 

The constructors of microscopes whose instruments have been in high- 
est repute since the introduction of Mr. Lister's improvements, have 
been, in England, Messrs. Smith, Beck & Beck, a house now only 
represented by Mr. J. Beck, nephew of Mr. Lister ; Mr. Andrew Ross, 
who has been succeeded by Mr. T. Boss, his son ; and Messrs. Powell 
& Lealand, already mentioned above ; and in France, Mr. Ober- 
hauser, who has given place to Mr. E. F. Hartnack, and Messrs. Xachet 
& Son, whose excellent instruments are well known in this country. 

Of American constructors there are several whose objectives will bear 
severe comparison with those of the best foreign makers. The earliest 
among those to secure for our country a distinguished position in this 
honorable rivalry was Mr. Charles S. Spencer, of Canastota, Xew York. 
There was claimed for Mr. Spencer's microscopes, it is believed with jus- 
tice, a decided superiority to any that had been previously constructed 
abroad in respect to resolving power ; and they continue still to com- 
pare favorably with the best ; but it is now some years since Mr. Spen- 
cer voluntarily abandoned a field in which he had won so distinguished 
laurels, and in the meantime there has been sensible improvement in 
the work of foreign makers. Fortunately, however, the retirement of 
Mr. Spencer did not leave our country unrepresented in this important 
branch of constructive art. A worthy successor to his skill and inher- 
itor of his honors presently appeared in the person of Mr. Robert B. 
Tolles, also originally of Canastota, but at present the superintendent of 
the Boston Optical Works, whose objectives are unsurpassed in excel- 
lence by any in the world. Mr. William Wales, of Fort Lee, near Xew 
York, contests closely with Mr. Tolles the palm of superiority: and 
between these two accomplished constructors the microscopic world 
has not been able to pronounce a decision more favorable to one than 
to the other. Besides these, our country has a number of other construct- 
ors of excellent microscopes, among whom are pre-eminently entitled 
to be mentioned, Messrs. J. & W. Grunow, of New York, and Mr. J. 
Zentmayer, of Philadelphia. 

Several important imj)rovements in the form and accessories of the 
microscope have originated also in the United States. The stage indi- 
cator for finding minute objects with high powers, which since its sug- 
gestion has assumed a variety of forms in the hands of different con- 
structors, was invented by the late Professor Bailey, of West Point, a gen- 
tleman to whom microscopic science is indebted for many valuable con- 
tributions; and the inverted microscope of Dr. J. Lawrence Smith, of 
Louisville, Kentucky, furnishes to the chemical investigator a most 



AMERICAN AND EUROPEAN MICROSCOPES. 535 

important addition to his resources ; preventing as it does tlie obscura- 
tion of the view by the condensation of vapors, and securing the instru- 
ment against injury from the action of corrosive fumes. Microscopists 
have also been much indebted to Professor Hamilton L. Smith, now of 
Hobart College, Geneva, New York, for various ingenious improvements 
of microscopic apparatus, among which may be mentioned his illumina- 
tor for opaque objects, in which the light is received upon a mirror within 
the tube behind the objective, through an aperture in the side, and is 
thrown down upon the object through the objective itself; his " mechani- 
cal finger, " an instrument for picking up with facility and precision, 
upon the point of a hair, objects invisible to the naked eye, separating 
the different species when mixed, and arranging them conveniently for 
observation ; and his binocular eye-piece, for use with high powers of 
the instrument, the only eye-piece of this kind which has as yet satisfac- 
torily solved this difficult practical problem. 

The number of microscopes present in the Exposition of 1867 was very 
great. It is a circumstance very strikingly evidencing the growing 
demand for instruments of this class that the business of constructing 
microscopes for ordinary use has recently developed itself into a regular 
manufacture. The consequence has been an immense reduction in prices ; 
so that the possession of an instrument really useful and meritorious is 
no longer the exclusive privilege of persons of large means. In Paris, 
the house most remarkable for the cheapness of its microscopes, tele- 
scopes, and other optical apparatus, is that of Mr. Alexander Lebrun, 
Eue Chapon, No. 25. Mr. Lebrun has a very large manufactory at St. 
Pierre-les-Bifcry, where the instruments are for the most part actually 
constructed. He furnishes a very neat, well-constructed microscope, 
with achromatic lenses superposed in the manner so familiar to those 
who have used the Chevalier microscopes, with two oculars, and a con- 
densing lens for opaque objects, all compactly arranged in a substantial 
box, for fifty francs — say ten dpllars. His models less complete in 
details range at lower prices down to four and a half francs, which is the 
price of a small microscope with a single objective and a single ocular. 
Mr. Lebrun's prices for portable telescopes, marine glasses, reading glasses, 
prisms and other optical apparatus, are similarly moderate. A pocket 
telescope, for instance, with a one-inch objective of sixteen inches focus, 
having a mahogany tube, and three draw-tubes of brass, is furnished 
at a cost of only five francs. And a larger instrument of the same kind, 
with an objective of 2.4 inches, focal length of four feet, and four draw- 
tubes, costs but fifty francs. It is not to be supposed that, because these 
prices are so low, the workmanship is inferior. On the other hand, 
these instruments are elegantly finished, the metal work is highly 
polished, the external tubes are varnished, rubbed down and similarly 
polished, and the Optical performance admirable. With one of these lit- 
tle telescopes, the writer found no difficulty in reading the hour on the 
clock dial of the ficole Militaire, at a distance of nearly two miles. 



536 PARIS UNIVERSAL EXPOSITION. 

In London, microscopes of very good quality are furnished at prices 
which approximate, as it respects cheapness, very nearly to those of 
Mr. Lebrun. A very good assortment of such will be found at the estab- 
lishment of Mr. W. E. Statham, ]N T o. Ill, Strand. Mr. Statham con- 
structs a variety of patterns and sizes of u youth's" and "student's*' 
microscopes, varying in price from half a guinea to about four pounds ; 
but he also constructs the more expensive forms of stands, and the 
superior objectives on the Lister principle, for prices correspondingly 
greater. 

In our own country, Messrs. Pike in Xew York have long been known 
as constructors of philosophical apparatus, from whom microscopes in 
every form may be obtained ; and it is believed that this firm is able to 
supply instruments of this class of a popular character, on terms which 
will favorably compare with those offered by London makers. 

Many admirable microscopic objectives constructed on the Lister 
principle were exhibited at the Exposition, chiefly by French, English. 
Swiss, and American makers. Some of those by Mr. E. F. Hartnack, of 
Paris, embraced a novel feature, called by him double correction. To 
understand this it is to be observed that the adjustment of the Lister 
combination, by which the aberrations of the several lenses of the sys- 
tem are balanced, is made on the supposition that the object to be viewed 
is placed before the objective without any intervening refracting medium 
except the air. But the preservation and security of the more delicate 
microscopic objects requires that they should be protected by a covering 
of thin glass ; and this, although its thickness does not in general exceed 
ji^ of an inch, and is often much less, produces a new aberration, which 
confuses the image, and in the case of objectives of high power, utterly 
destroys the distinctness of definition. The principles which guided Mr. 
Lister in the original adjustment of the combination suggested to him a 
simple means of correcting this confusion, which consists in slightly 
increasing the distance between the front lens of the system and the two 
others behind it. The observer is euabled to make this correction for 
himself, by turning a milled ring near the front of the objective until the 
distinctness of the image is restored. There is a limit beyond which this 
correction cannot be carried ; and if the thickness of cover is too great 
to be dealt with in this way, the attempt to observe must be abandoned. 
Mr. Hartnack's system of double correction consists in making the dis- 
tance between the second and third of the lenses of the system varia 
ble, as well as that between the first and second. Both the movements 
required to produce this double effect are made simultaneously by means 
of the same ring ; and the advantage which Mr. Hartnack claims for the 
improvement is that it permits the use of a thicker cover for the object 
observed. 

The only other point of new interest which presented itself in the 
examination of the first-class objectives exhibited was found in the 
application by Messrs. Hartnack and Xacket to the construction of 



BINOCULAR MICROSCOPES. 537 

their most recent lenses, of what is called the principle of immersion, a 
principle first suggested in 1855 by Professor Amici, of Florence, and 
actually reduced by him to practice at the time. This principle is appli- 
cable only to those powers which approach in use very closely to the object 
observed; and it consists in introducing between the objective and the 
covering glass of the object a drop of water in which the lens is 
immersed, to the exclusion of the intervening stratum of air. Although 
the great advantage obtainable by the use of this simple expedient was 
practically demonstrated by its originator twelve or fourteen years ago, 
in the superior performance of the objectives constructed by him with 
his own hands, the method was received with indifference or distrust 
by professional opticians, who continued by preference to construct all 
their objectives upon principles to which they had been long accustomed. 
Some three or four years ago Mr. Kachet revived the idea of Amici, 
and commenced the construction of immersion lenses, to the great 
improvement of his instruments. In this he was shortly afterward fol- 
lowed by Mr. Hartnack. 

The great superiority in resolving power between the "wet." and the 
"dry- working" lenses was very manifest in the comparisons made at 
the Exposition. The result has been to induce many makers to adopt 
the Amici principle in their more recently constructed high-power 
objectives ; and among these Messrs. Tolles and Wales, in this country, 
and Messrs. Powell and Lealand, of London, have been pre-eminently 
successful. It is not necessary for Americans any longer to go abroad 
in order to obtain microscopic glasses of any description of the highest 
order of excellence. The objectives of Messrs. Tolles and Wales, 
whether constructed for working wet or dry, will stand the severest 
comparison with those of the most successful constructors of England 
or France. 

Another particular in respect to which there has been a material 
improvement in the recent forms of microscopic apparatus, consists in 
the adaptation of the instrument to binocular vision. The use of two 
eyes instead of one is attended with a very sensible relief to the observer, 
and tends to prevent the injury to the sight which may result from the 
unequal use of the organs. But there is, in a strictly scientific point of 
view, another and a very signal advantage gained by the use of the 
binocular form of the instrument, and this consists in the important aid 
to the judgment in regard to the real structure of microscopic objects, 
which is derived from the stereoscopic effect of biu ocular vision. It is 
unnecessary to add that not only is the comfort of the observer pro- 
moted by this mode of observation, but his pleasure in observing is 
also greatly enhanced by seeing objects in all their three dimensions, in 
their depth as well as in their length and breadth. 

After the discovery of the true secret of binocular vision by Professor 
Wheatstone in 1838, but especially after the construction of the len- 
ticular stereoscope by Sir David Brewster, in 1852, and its introduction 



538 PARIS UNIVERSAL EXPOSITION. 

into general use, the thought of making this principle available in 
microscopic observation came naturally without doubt to many minds ; 
but the first reduction of this thought to a practical form was made by 
the late Professor J. L. Eiddell, of the University of Louisiana, in Xew 
Orleans. Professor Eiddell employed a pair of small rectangular prisms, 
with their bases in a common plane and joined by the acute angles at 
the base, immediately behind the objective, to split the emergent pencil 
into two equal portions, which were reflected horizontally right and left. 
A second pair of similar prisnis received these horizontal rays, and by 
a second reflection sent them in the direction of the observer. In this 
manner the rays which belong to the right half of the pencil reflected 
are conveyed to the right eye ; and those which belong to the left half 
of the same pencil are conducted to the left eye. If, therefore, the rays 
were not crossed in the objective, that is to say, if the image were erect, 
the stereoscopic effect would be true ; but as such a crossing does take 
place with an accompanying inversion and reversal of the image, the 
stereoscopic effect is reversed also, and becomes what is called pseudo- 
scopic. The object is presented, indeed, in three dimensions, but its 
reliefs are depressions and its depressions are reliefs. Other forms of 
the apparatus, early suggested, were liable to the same objection. The 
earliest truly stereoscopic binocular microscope constructed appears to 
have been that of Mr. Xachet, in which an equilateral prism was 
employed to effect the separation of the pencil by internal reflection 
from the inclined sides, the light from the objective being received per- 
pendicularly upon its base. Two other similar prisms by subsequent 
reflection directed the two halves into which the original pencil was 
thus divided to the eyes of the observer. These two halves, from the 
manner of their reflection in the first prism, necessarily crossed each 
other before emergence, and by this means the pseudoscopic effect which 
had attended the former constructions was prevented. 

Theoretically, the binocular microscope of Mr. Xachet is unexcep- 
tionable ; practically, it is difficult for many observers to make the two 
images coalesce. This seems to be owing to the fact that the two eye 
tubes are perfectly parallel, whereas it greatly facilitates the recognition 
of two images as belonging to the same object, to present them in such 
a manner that the axes of the eyes must be slightly inclined toward 
each other in order to receive them. For this reason in part, but more 
perhaps on account of the greater simplicity of construction, the well- 
known YTenham binocular, in which the division of the compound 
pencil is effected by means of a trapezoidal prism, has met with more 
general favor ; and this form of the instrument has come extensively 
into use in England and in this country. 

Mr. Cachet has recently introduced a binocular microscope of a much 
simpler description than his original one, which possesses the recom- 
mendation of being applicable to an ordinary instrument without alter- 
ing its construction or interfering with its usefulness as a monocular. 



NACHET'S BINOCULAR MICROSCOPE. 



539 



An opening is simply made in the side of the body, immediately behind 
the objective, into which is introduced Fig. 109. 

a rectangular prism carried in a mount- 



ing of metal, which reflects half the com- 




pound pencil horizontally, and this is 
received upon another prism which d 
rects it to the eye of the observer. The 
instrument, which is not particularly 
sightly, is represented in the figures 
annexed. Fig. 109 is a view of the instru 
meut with the parts united; Fig. 110 
shows the principal parts separate, and 
illustrates the manner in which the di- 
viding prism is introduced. In order 
to accommodate the two tubes to the 
varying distance between the eyes of 
different observers, the horizontal part 
containing the prisms was originally 
made with sliders; but in the form 
which was exhibited in the Exposition, 
the extra tube has an angular move- 
ment around its lower extremity as a 
ceptre. This involves the necessity of 
a corresponding movement of the re- 
flecting prism at the centre of motion, 
to one-half the same angular extent. 
Mr. Nachet has contrived an ingenious and simple combination of levers 
by which both movements are produced in their due proportion on turn- 
ing a single milled head. 

This form of the binocular microscope is at- Pig- HO. 

tended with an advantage pecidiar to itself. It 
has been observed above that true stereoscopic 
vision requires that the two halves into which the 
compound pencil is divided behind the objective 
should cross each other, so that the right eye may 
receive the left-hand half and the left eye the 
right-hand half. The rectangular prism when in- 
troduced through the side of the body must there- 
fore be advanced so far as to reflect the opposite 
half of the compound pencil, while it leaves the 
adjacent half free to pass. But if this prism, of 
which the position can be controlled by means of 
a slider, is drawn toward the extra tube so as to p ar ts separated, 

reflect the nearer half of the compound pencil and to allow the opposite 
half to pass freely, the conditions will be such as to produce pseudoscopic 
vision, and to present an image in which the reliefs shall appear as 



Nachet's Binocular Microscope. 




540 



PARIS UNIVERSAL EXPOSITION. 



depressions and the depressions as reliefs. In the examination of an object 
of obscure structure, the contrasts of appearance thus presented are often 
very serviceable in contributing to the formation of correct judgments. 
It is a disadvantage common to all the forms of binocular microscope 
above mentioned that they perform well only with objectives of com- 
paratively low power. In fact, it is obvious that a performance theoret- 
ically perfect would require not only that the division of the compound 
pencil emerging from the objective should be exactly equal, but that 
each of the simple pencils of which the compound pencil is made up 
should also be equally divided. Such an equality could only be per- 
fectly secured by making the division in that plane or cross-section in 
which the axes of all the simple pencils cross, which would be really the 
plane passing through the centre of the front lens. At any distance 
behind this plane the simple pencils are more and more unequally 
divided, in proportion as they proceed from points more and more 
distant from the axis. And inasmuch as with the higher powers the 
cross dimensions of all the pencils are proportionally reduced, it follows 
that a division which must necessarily take place at some distance 
behind the innermost glass of the objective will become increasingly 
unequal as the power increases. A practical limit is therefore soon 
found to the availability of a binocular system in which the division is 
effected in the manner above described. 



Fig. 11 J, 




This disadvantage led to the suggestion, two or 
'e 1 three years ago, by Mr. Wenhain, of a method of 
dividing the pencil by the interposition of a transpa- 
rent plane reflector, which, by being adjusted to a 
proper inclination, might reflect one half the light of 
each pencil, and allow the other half to pass through. 
This plan involves necessarily the sacrifice of stereo- 
scopic effect, but it secures to the observer the great 
comfort and benefit which results from the equal use 
of the two eyes. It has proved practically somewhat 
difficult to carry out satisfactorily this idea of Mr. 
Wenham. His own first form of the instrument did 
not satisfy himself. More recently, Messrs. Powell 
and Lealand, of London, have patented a combination 
of prisms, which is believed by them to accomplish 
the object aimed at as well as could be reasonably 
demanded. This is represented in the figure annexed. 
The compound pencil from the objective, indicated by 
the line op, is partially transmitted through the quad- 
rangular prisin A, and partially reflected to the tri- 
angular prism B, by which it is again reflected to 
the eye. The two halves of the original pencil cross 
at s, for the purpose of preventing pseudoscopic effects : 
but this is unnecessary, since to the ordinary observer 



BINOCULAR MICROSCOPES— TOLLES'S EYE-PIECE. 541 

there is no perception of relief, either true or false, produced by the 
combination. The disadvantage of this system is a great inequality of 
light in the two fields ; the image formed by reflection being much 
inferior to the other in brightness. There is also a considerable loss of 
light by reflection at the second surface of the rectangular prism. Not- 
withstanding these disadvantages, this binocular is a valuable contri- 
bution to the resources of microscopists, many of whom profess to 
experience from the inequality of illumination no serious inconvenience. 

As a convenient mode of distinguishing the two classes of binocular 
microscopes from each other, this which has last been described may be 
called the catadioptrie instrument, implying that the division of the 
pencil is made by reflection $ and the former the stereotomic, which 
expresses a division geometrically or mechanically made by cutting 
through the solid represented by the bundle of rays. 

Mr. E. B. Tolles has constructed an instrument on the stereotomic 
principle, designed to remedy the difficulty above pointed out as attend- 
ing the original binoculars ; while at the same time it secures the inciden- 
tal advantage of permitting any ordinary single-tubed microscope to be 
used as a binocular. This is a double eye-piece provided with a system of 
prisms in all respects like those of Mr. Cachet's earliest form of binocular 
microscope, but designed to divide the compound pencil of light at a 
distance from the objective about equal to that of the ordinary eye-pieces. 
From what has been said above as to the necessity, in order to secure 
equality, of making the division where the axes of the pencils cross, it is 
obvious that the method of Mr. Tolles is only available on condition 
that the axes be made to cross a second time ; that is, that the erecting 
form of eye-piece be employed. An eye-piece of this description pro- 
duces, first, an inverted image of the object, and secondly, a direct 
image, which is the image seen. Between these two images the pencils 
cross, and the point of crossing is the proper place for the dividing- 
prism of the binocular eye-piece. Siuce the image observed has the same 
position as the object itself, it would seem at first thought that the divis- 
ion of the compound pencil ought to be made in the manner employed by 
Dr. Biddell, by means of rectangular prisms ; but such a construction, par- 
adoxical as the statement may seem, leads to pseudoscopic effects. The 
equilateral prisms of Cachet are used by Mr. Tolles, and each half of the 
divided compound pencil is sent to the opposite eye. The necessity for 
this mode of distribution will be recognized if we disregard the real 
object and the objective, and consider the first image to be itself the 
object under observation. The conditions are then the same as present 
themselves in Nachetfs original binocular. In that case, if the eye could 
be put in place of the dividing prism and the objective taken out of the 
way, the real object would appear in its natural position. But the 
objective inverts the object, so that when the image is duplicated by 
means of the dividing prism, the halves must cross in order that each 
may reach the eye to which it belongs. In the binocular eye-piece under 



542 



PARIS UNIVERSAL EXPOSITION. 



consideration, the eye placed at the point occupied by the dividing 
prism would see the inverted image as if it were a real object ; and as 
this image is again inverted afterwards, the same necessity exists as 
before for crossing the halves of the divided compound pencil. 

As the point of second crossing of the simple pencils is invariable in 
position, this eye-piece works with objectives of all powers and with 
perfect equality of illumination in both fields. It is liable to the 
objection of a loss of light by the multiplication of surfaces of transmis- 
sion ; but this is not greater than attends the catadioptric binoculars 
thus far invented. Moreover, Mr. Tolles has pointed out the possibility 
of reducing the number of surfaces so that it shall not exceed the num- 
ber necessary in an ordinary binocular, by giving a spherical curvature 
to the surfaces of transmission of the prisms employed, and thus com- 
bining a lens, or two lenses, and a prism in one solid ; but it is believed 
that he has not as yet illustrated this possibility by a practical example. 
A new form of catadioptric binocular has been proposed by Professor 
H. L. Smith, and described by him in the American Journal of Science for 
January, 1888, which much more equally divides the compound pencil 
than the combination of Messrs. Powell and Lealand described above, 
and on this account is more satisfactory to those observers who find 
inconvenience from the unequal illumination spoken of as occurring in 
that. The diagram here presented shows the essential parts of Professor 
Fig. 112. Smith's device. A thin transparent plane reflector 

is shown at ab. A ray of light proceeding from the 
object encounters this reflector at the point _p, and 
is in part transmitted without change of direction 
in pe, and in part reflected, encountering the trun- 
cated rectangular prism c, in which it undergoes a 
second reflection to correct the reversal produced by 
the first, aud emerges in the direction d. The inequal- 
ity of illumination mentioned as occurring in the 
binocular of Powell and Lealand is a consequence of 
a too small angle of incidence upon the first reflect- 
ing surface. In Professor Smith's instrument, the in- 
clination of the mirror to the incident ray is such as to 
produce a sensible equality between the intensities of 
the reflected and transmitted light. An inclination of 
the plane of the mirror 80° to the axis of the telescope 
has been adopted by Professor Smith, and is found to 
answer the purpose. It was the original design of 
the inventor to make the reflector so far wedge- 
shaped as to throw the reflection from the second 
surface out of the field, but actual experiment showed 
that a very slight inclination of the two surfaces to 
each other was sufficient to make the two images 
coalesce, at least for a determinate position of the eye-piece, which is 




DOUBLE AND TRIPLE MICROSCOPES. 



543 



Fig. 113. 



easily found by trial. The only instruments as yet made on this plan 
have been constructed by Professor Smith with his own hands. The 
writer, by actual experiment, has found the performance to be in a high 
degree satisfactory. 

Mr. Nachet exhibited in the Exposition a binocular dissecting micro- 
scope of a neat and compact form; and another still simpler was exhib- 
ited by Mr. J. Beck. 

The division for purposes of binocular 
vision of the compound pencil of light 
proceeding from the objective, suggests 
naturally the adaptation of the instru- 
ment to the use of two observers simul- 
taneously. A double microscope con- 
structed on this principle by Mr. Cachet 
is represented in the accompanying fig- 
ure. It is obvious that, after the division 
of the beam, it is only a matter of mechan- 
ical detail to give to the parts any direc- 
tion which may be found most conven- 
ient. For purposes of demonstration, or 
in the prosecution of concerted observa- 
tion, simultaneous observation of the same object is not only convenient, 
but is also greatly economical of time. Moreover, when the objects 
observed are moving, it is next to impossible for two observers succes- 
sively to identify the same aspects. These considerations give great 

Fig-. 114. 




Double Microscope. 




Nachet's Triple Microscope. 

practical value to the double microscope when used for purposes of 
instruction ; and to those who observe merely for the satisfaction of curi- 



544 PAEIS UNIVERSAL EXPOSITION. 

osity they add very niuch to the interest of the observation, and the 
attending gratification. These remarks are still more applicable to 
the triple and quadruple forms of the instrument constructed by the 
same ingenious maker. The triple microscope of Mr. Xachet, as exhib- 
ited in the Exposition, is represented in Fig. 114. The beam of light 
from the objective is here divided into three equal parts by a com- 
bination of prisms of suitable form, each portion being reflected into 
a separate tube. As the eyes of different observers require different 
adjustments, each one of these tubes has a sliding tube within it, by 
means of which a large movement may be given to the eye-piece, per- 
mitting it to be adjusted separately to the point of most distinct vision ; 
while a preliminary general adjustment for the Avhole may be obtained 
by means of a rack and pinion which varies the distance of the objective 
from the object. 

By reference to the figure given further back, of the more recent form 
of binocular introduced by Mr. Xachet, it will be observed that a slight 
modification of the second reflecting prism would suffice to convert that 
binocular into a double microscope for two observers. Or, in fact, since 
in this case the secoud tube may be definitely fixed in its inclination to 
the first, a single prism of four or five sides might be substituted for the 
two of the binocular, with the advantage of diminishing the loss of light 
by the suppression of two of the surfaces of transmission. By this means 
any ordinary microscope may be converted, temporarily or permanently, 
into a microscope for two observers, at a comparatively trifling expense. 
This form of double microscope, as constructed by Mr. Xachet, perform s 
very satisfactorily. 

In conclusion, it may be observed of the microscopes and microscopic 
apparatus exhibited at the Exposition, that the advantage in regard to 
display was altogether on the part of the British exhibitors, while the 
superiority in respect to performance must be ascribed to the immersion 
lenses of the French. The microscope stands of the continental makers 
are much less elaborate than those of the English, or those preferred by 
our own observers. The American objectives of Messrs. Wales and 
Tolles were presented under some disadvantage, since they were unac- 
companied with stands, but their merit was recognized by the jury and 
they were very honorably distinguished in the awards. 

The neglect of the American exhibitors to send out stands was the 
more to be regretted, inasmuch as the stands made by some of them are 
admirable in design, convenient in use, and superior in workmanship. 
Nothing could be more elegant or tasteful than the first class stands 
constructed by Zentmayer, of Philadelphia. Mr. Tolles has also pro- 
duced very fine stands. A masterpiece of this kind, constructed by 
him from designs furnished by the present reporter, possesses some 
important and peculiar advantages. The movable stage is provided 
with two tables, one facing, as usual, upward, and the other facing down- 
ward, which are firmly connected together, and have a common move- 



MICROSCOPES STATIC ELECTRICITY. 545 

ment, controlled on both sides by milled beads in both co-ordinate direc- 
tions. When the object is used on the inferior stage, it is secured by 
spring clips, easily managed. In this case the central part of the supe- 
rior table, which is removable, is taken away, and the objective descends 
through the opening. Any degree of obliquity of illumination, extend- 
ing even to ninety degrees, can by this arrangement be brought to bear 
upon the object — an advantage which is secured by no other form of 
stand. The stage of this instrument is also capable of revolution on 
the optical centre throughout the whole circle. The same thing is true 
of the latest improved stands constructed by Messrs. Powell and Lea- 
land; but in these there is the disadvantage that, in certain azimuths, 
the double milled heads controlling the movements are inaccessible, and 
the movement of the stage is possible in only one of the co-ordinate 
directions ; while in the stage by Mr. Tolles, above spoken of, when one 
pair of milled heads is out of reach the other pair is always available. 
This instrument is also distinguished by numerous minor peculiarities, 
which greatly facilitate observation and promote convenience of man- 
agement. 

YI._ELECTEICITY. 

Instruments intended for the illustration of electrical phenomena, or 
designed as aids to experimental research in electrical science, arrange 
themselves naturally under the two heads electrostatics and electro- 
dynamics. In considering the electrical apparatus exhibited in the 
Exposition, this distinction will be observed. 

STATIC ELECTRICITY. 

The forms of electrostatical apparatus which have in late years excited 
the highest interest, have been those in which advantage is taken of a 
disturbed state of electrical equilibrium produced by induction, to accom- 
plish the direct transformation of mechanical force into electricity. Of 
the several machines operated upon this principle which have obtained 
a certain favor, that which is most widely known, at least in this coun- 
try, is the one which is named from its inventor the Holtz electrical 
machine. Next to this, the most remarkable are the machines of Topler, 
of Eussia, and of Bertsch, of Paris. All of these illustrate the direct 
transformation of mechanical force into electricity ; and all of them, as 
it respects construction, are essentially transformations into a new shape 
of the simple, and as commonly constructed quite inefficient, apparatus, 
called the electrophorus. 

The idea of accumulating electricity by multiplying the effects of 
induction is not entirely new. Several forms of the condenser have been 
constructed expressly to apply it. Thus, the three-plate condenser of 
Peclet is designed to afford the means of obtaining electricity of high 
tension; though the quantity accumulated by it is after all very trivial, 
while the process of accumulation is both slow and troublesome. In 
35 1 A 



546 PARIS UNIVERSAL EXPOSITION. 

1848, Svanberg described to the British Association for the Advance- 
meat of Science an arrangement superior to Peclef s for accomplishing 
the same object; but this, too, was an apparatus too difficult success- 
fully to manipulate, and too slow in producing results, to be of any prac- 
tical use. Yet Svanberg's apparatus, properly managed, was capable 
of producing sparks from a single cell of Daniell's battery. 

In 1862, Mr. C. M. Varley, of London, electrician to the Atlantic Tel- 
egraph Company, exhibited at the international industrial exposition an 
instrument by means of which feeble electrical tensions could be multi- 
plied several thousand fold; and this without any of the troublesome 
operations by hand which made the methods of Peclet and Svanberg 
tedious and uncertain. A simple rotation was substituted in place of a 
complicated series of transfers, and mechanical contacts took the place 
of contacts with the finger. Mr. Varley's machine was therefore per- 
fectly uniform in the results which it produced; the total effect being- 
proportional to the number of rotations given to it, and being capable 
of calculation in advance. In exhibiting the performance of his instru- 
ment to the jury, Mr. Varley furnished a practical proof of this uni- 
formity of action by first multiplying the tension of the positive pole of 
a Daniell's cell by a definite number of rotations, and measuring the 
intensity of the accumulated charge by means of a portable Thompson's 
electrometer; and afterwards reversing the direction of rotation and 
turning twice as many times in the opposite direction, and measuring in 
the same manner the final resultant, which was negative and which 
proved to be of an intensity almost exactly equal to the first. Sparks 
were produced by this machine from a single Daniell's cell without diffi- 
culty, and Mr. Varley stated that he had obtained a multiplication 
amounting to fifteen thousand times the tension of the original source. 
As this machine was the first in which the accumulation of electricity 
by influence, in a continuous manner, in considerable quantities, and of 
a high degree of tension, was practically proved to be possible, it is but 
justice to the inventor, although his machine has not come into general 
use, that, in a matter of so much scientific interest, he should receive 
the credit due to an undoubted priority. 

Before proceeding to speak of the machines of more recent inventors, 
it will not be out of place to present a brief description of the earlier 
form of static induction apparatus contrived by 3Ir. Varley. The fol- 
lowing account of this apparatus is transcribed from the reports of the 
jury on the Exposition of 1862. 

varley's static induction apparatus. 

"The instrument might be called a multiplying inductor. It consists 
of an axis on which parallel rows of insulated brass vanes or arms are 
fixed; the description will be simplified by considering one row of vanes 
only, A, B, C, D, &c. The axis may be turned by hand, and at two 
points of the revolution diametrically opposite to each other the vanes 



ELECTRICITY STATIC INDUCTION APPARATUS. 547 

enter two rows of hollow insulated coverings or shells of brass, «, a h 
a 2j a 3j &c, and &, b h b 2 , hi &c. These shells conceal the vanes entirely on 
three sides, and are connected one with another as follows : a uncon- 
nected, ai a 2 joined together, a 3 a A joined together, a 5 a 6 joined together, 
&c. In the opposite row b bi are joined, b 2 b 3 joined, & 4 b 5 joined, &c; a 
is opposite b, % opposite & 1? &c. Thus the two rows may he said to be 
arranged in alternate insulated couples. 

" The charge to be multiplied is communicated to «, and we will first 
suppose this charge to consist of a certain definite quantity, retained 
without loss by means of perfect insulation. The axis is next turned 
round by hand ; when the vane A is inside a, an earth connection is 
made at the inner end of the vane A, where it is not covered by the 
shell. If the charge on a be positive, a negative charge of correspond- 
ing magnitude will be induced on A. The charge so induced may 
approach more or less nearly, according to the proportions of the instru- 
ment, to equality with the charge on a; it will always be somewhat less, 
but can easily be made in practice to differ very little from the original 
charge. When the axis is turned round still farther, the earth con- 
nection is broken, and the negative charge remains insulated on the 
vane A. As the axis continues to revolve, the vane A is brought inside 
the shell &, and is then put in connection with the shell b 6 X by a suita- 
ble contact. The negative charge on A will then almost entirely dis- 
tribute itself over the outer surface of the double shell b b l . As the axis 
is turned round and round, the same series of contacts will be repeated ; 
successive charges on a will be induced by a, and communicated to the 
double shell b & 1? on the surface of which these charges will gradually 
accumulate, tending towards a limit which is only not infinite, (leaving 
insulation out of consideration,) because when the vane is inside b b^ 
and its contact there made, its Whole metal is not surrounded by a closed 
metal forming part of b. The effect will, however, practically be limited 
rather by imperfect insulation than by the want of continuity in the 
surrounding surface of b b x . But while negative electricity is thus 
accumulating on b b i7 the second vane, B, has been continually passing 
through the shell b x . At the moment when fully covered by this shell, 
an earth contact has been made with this vane as already described by 
vane A. B has, therefore, been receiving continually greater charges 
of positive electricity, each very nearly equal to the quantity of nega- 
tive electricity at that time on b b h and these in their turn it has com- 
municated to the shells a x a 2 . The vane C receives continually increas- 
ing negative charges from a x a 2l which it communicates to b 3 & 4 , and 
thus the multiplication proceeds through any required number of vanes 
and shells, by the simple process of turning the axis. 

"If all the vanes and shells be alike, and if one vane with its pair of 
shells can, at most, produce a charge in the second shell only ten times 
greater than that in the first, it is clear that ten vanes and their shells 
would produce a maximum charge in the final shell 10 10 , or 10,000,000,000 



548 PARIS UNIVERSAL, EXPOSITION. 

tion which it has just completed. In the mean time Q has received and 
times greater than that on the first shell. The tension of this final 
shell, if all disturbing causes be removed, would likewise be 10,000,000,000 
times greater than that of the first shell under similar circumstances. 
Metallic screens in connection with the earth are used between each 
pair of coupled shells to prevent their action one on the other, and also 
surrounding the whole apparatus to screen it from irregular electric 
induction. If, instead of giving the first shell a a certain definite 
quantity of electricity, it were maintained at a certain constant by con- 
tact with a source of electricity, (for instance connected with one plate 
of a battery, while the other is in connection with the earth,) the result 
would be exactly similar to that which would be obtained if a definite 
quantity, equal to that contained in the shell a when the vane A is 
inside it and the earth contact made, has been communicated to the 
shell a in the first instance. The actual multiplication for each number 
of turns would, when the insulation is good, be perfectly definite 5 but 
could in this arrangement be practically determined by experiment only. 
It was understood that Mr. Varley has, by slightly modifying the present 
arrangement, produced an instrument in which it is easy by calculation 
to determine the multiplication given by any fixed number of turns." 

The electrical machines of Holtz and Topler made their appearance 
almost simultaneously in 1866. The machine of Holtz is already quite 
extensively used in the United States as well as in Europe. It is con- 
structed in an elegant form by Eitchie, of Boston, and also by the 
Messrs. Chester & Co., of New York. Topler's is hardly known in our 
country at all. In both these machines a rotating disk is employed to 
carry electricity from a point where it is excited by influence to another 
point where it is accumulated. In Holtz's machine the carrier is a non- 
conductor, being the rotating disk itself, which is formed of glass. In 
Topler's, in which a glass disk is also used, the use of the disk is to 
insulate a pair of conducting carriers 5 so that this machine has a pretty 
direct resemblance to that of Mr. Varley. 

topler's electro-static induction machine. 

Topler's machine will be first briefly described : In the annexed figure, 
on page 549, which represents only the essential parts of the instrument, 
without the sustaining frame, a circular plate of glass is shown, mounted 
on the axis EE', to which is attached a crank. In point of fact, the 
velocity of rotation given to the disk, in practice, is greater than can be 
directly imparted by the hand ; and the axis EE 7 is turned by a pulley 
driven by a larger wheel, to which the power is immediately applied 
by means of a band. The disk is coated, over a pretty large extent of 
the surface of each semi-circle, by tinfoil sheets, P and Q. These sheets 
are applied on the side of the disk toward the fixed plate P', and are 
made large enough to fold over the circular edge and admit of being 
pasted down, so as to form on the crank side of the disk the annular 
coatings p q. These sheets and annular bands are separated from each 



TOPLER'S ELECTRO-STATIC INDUCTION MACHINE. 



549 



otlier by an intervening space of uncoated glass. The fixed plate P' was 
originally constructed by the inventor, of metal, insulated by the three 
supports s s' s", and placed at a distance of not more than live milli- 

Fig. 115. Fig. 116. 

f 




Construction of Topler's Machine. 

meters from the disk ; but he has since, for a reason which will presently 
appear, made it of thin glass, coated, on the side most distant from the 
disk, with a sheet of tinfoil equal in size to P or Q. Two 'vertical con- 
ductors, and C y , are attached to the horizontal insulating supports 
shown in the figure j and are put into communication with each other 
or with the ground, at pleasure, by means of the wires /and/ 7 . To the 
conductors and C, are added the rods and knobs b and &', which last 
are furnished with points directed toward each other and adjustable at 
different distances. The conductors are also put into communication 
by contact with the bands p and g, by means of light metallic springs 
r and r'. 

Such being the construction of the machine, its operation is as fol 
lows : P' is put into conducting communication with some feeble but 
constant source of negative electricity, as, for instance, the negative pole 
of a dry-pile. The conductor C is made to communicate with the ground 
by means of the wire/; and C 7 is insulated. The negative electricity of 
P' induces a positive charge in P, which, in the course of the rotation, 
is in conducting communication with 0, and therefore with the ground, 
until the moment before it reaches the position represented. Its own 
negative electricity, therefore, escapes by that channel. In the position 
which, in the order of rotation, immediately succeeds that represented, 
P will be in communication with C by means of the spring r' ; and the 
positive electricity with which it is charged will pass off principally upon 
that. It will directly after come into communication with 0, and so 
will be restored to its natural state, and prepared to repeat the opera- 



550 PARIS UNIVERSAL EXPOSITION. 

carried a similar charge to O 7 , in like manner. There is a limit to the 
extent beyond which the accumulation produced by this succession of 
transfers cannot be carried. When the intensity exceeds a certain mod- 
erate amount, sparks begin to pass between P and P 7 . It was with the 
view to diminish this liability to a discharge, which neutralizes the 
power of the machine, that Mr. Topler substituted for the metal plate 
P 7 , a thin glass plate coated on the side most remote from P. He 
also thoroughly varnished the metallic coating P itself. These changes 
have been attended with improvement ; but they have not removed the 
difficulty. It is only possible to prevent a shower of sparks between P 
and P 7 , by substituting a discharge between C and C 7 , through the 
poiuts b and 1)'. A distance may be found by trial, at which if these 
points are fixed, the machine will work without a backward discharge 
upon the exciter P 7 . But this limits its power of accumulating electri- 
city upon a given conductor. Owing to the tendency by backward dis- 
charge to the neutralization of the excited condition of P 7 , it is neces- 
sary to maintain permanently the communication between this surface 
and the original and constant source of negative electricity. But Mr. 
Topler, by an ingenious expedient, has contrived to evade this necessity, 
by making the machine itself contribute the supply of electricity essen- 
tial to the maintenance of the excited state of P 7 . This consists in 
establishing upon the same axis EE a second disk and accompanying 
apparatus, forming a miniature copy of the first, as shown in Fig. 116. 
The only difference is that the exciting plate of the small apparatus, 
marked in the figure T 7 , is reversed in position from that of the large 
apparatus, which is P 7 . This second exciting plate communicates 
through the wire/ 7 with C 7 ; which last is charged, as we have seen, 
positively. T 7 is therefore positive, and T is accordingly negative, pro- 
ducing an accumulation of negative electricity in the conductor t ; which 
again imparts to P 7 through the wire connection represented, the con- 
stant supply of negative electricity necessary to maintain the activity of 
the large machine. The conductor V of the small apparatus communi- 
cates with the ground by the wire A. 

A curious fact manifests itself in the operation of the machine with 
these arrangements. In its original form, no electrical action would 
take place unless P 7 were first electrically excited by communication 
with some source of electricity exterior to the machine. In the modified 
form it excites itself. It is only necessary to turn it a few minutes in 
order to bring it into a condition of as high activity as can be desired. 
This effect is consequent upon the power of the machine to increase by 
accumulation the smallest original charge, even though it should be so 
small as to be quite insensible; or to add to a minute disturbance of 
equilibrium until it becomes a large one. If there is any unequal distri- 
bution of electricity in the machine, therefore, at the moment when it is 
set in motion, it will immediately charge itself. If there is no such ine- 
quality, it is not at first obvious how the initial disturbance of equilib- 
rium is produced. Topler ascribes it to the friction of the air, or of the 



ELECTRICITY STATIC INDUCTION APPARATUS. 



.51 



springs. The latter hypothesis is the most plausible, inasmuch as these 
springs run at intervals upon glass, and one of them is always insulated. 
Suppose, for instance, that by the friction of r' on the glass, this spring, 
with its connected conductor C ; , becomes positively electrified, however 
slightly, T' will become positive, and T t and 1 3/ negative. The condi- 
tions are now such as to induce the regular series of reactions which 
we have described, and to bring the machine speedily into a high 
state of activity. 

In the Eussian section, a Topler machine was exhibited by Mr. Wes- 
selhoft, of Riga, embracing a combination of ten or twelve plates. This 
was inclosed in a glass case, and designed to be permanently so. At 
one extremity of the box an aperture in the glass allowed the axis to 
pass through in order that the power might be applied externally. The 
machine, which was unfavorably situated for close examination, being 
hemmed in by other objects on exhibition, presented too great a compli- 
cation of parts to be easily made out in its details $ and it was neither 
exhibited in operation nor accompanied by any explanation. Of its 
powers of performance, therefore, nothing could be ascertained, although 
inquiry was made of gentlemen connected with the Russian commission. 
Topler's machine requires to be driven at the rate of fifteen to eighteen 
turns in a second. For reasons which Avill be apparent from the fore- 
going description, it does not furnish high intensity or produce long 
sparks 5 but the quantity it will generate in a given time is quite 
remarkable. With two disks mounted as above described, and of the 
diameters of ten and fifteen inches respectively, a Ley den jar exposing 
one hundred and sixty square inches of coated surface is charged in 
less than half a second. 

HOLTZ'S ELECTROSTATIC INDUCTION MACHINE. 



The machine of Holtz in 
its original form is shown in 
the accompanying figure. Its 
principal parts are, first, a 
thick circular plate of glass, 
secured by four horizontal 
supports vv v ■v 1 forming part 
of a frame 5 second, a very 
thin and rotating disk of 
glass, fixed to an axis, which 
passes through the thick plate 
by an aperture sufficiently 
large, and is driven by a pul- 
ley and multiplying- wheel op- 
erated by the handle M ; the 
thin disk is on the side of the 
thick plate most distant from 
the handle, and from the ob- 




Holtz's Electrostatic Induction Machine. 



552 PARIS UNIVERSAL EXPOSITION. 

server in this perspective view, but is very near it ; third, two sets of 
points, or electrical combs, in insulating supports, and with binding 
screws for the attachment of conducting wires C and C ; fourth, two 
openings or sectoral cuts, in the circumference of the fixed plate at F 
and F 7 , of each of which one of the straight sides in the radial direction 
is armed with a coating of paper furnished with points also of paper 
or card-board, placed parallel to the rotating disk, but having a direc- 
tion opposite to that of the rotation. 

In order to bring on electrical action by means of this machine, one 
of the paper armatures is charged with electricity by exciting a plate of 
glass, a stick of sealing wax, or a piece of ebonite, by friction, and 
bringing the excited body into contact with the armature. On turning 
the machine, electricity accumulates in the insulated conductors con- 
nected with the combs, and the second armature acquires an electricity 
opposite to that which was given to the first. The electricities of the two 
conductors are of the same name with those of their adjacent armatures. 
In order to bring on the action of the machine expeditiously, it is 
advisable to put 0, for a moment after exciting the armature, into com- 
munication with C. This precaution is, in fact, nearly indispensable. 

In order to understand this action, let us suppose, at first, that the 
armature a is charged positively, and the armature a' negatively ; and. 
for the sake of simplifying the matter as far as possible, let us consider 
what ought to be the effect, supposing that there is no rotation of the 
intervening disk. The inductive influence of a on the conductor con- 
nected with the adjacent comb will draw out of that conductor its neg- 
ative electricity, which will be intercepted by the glass and held there, 
while the positive electricity of the same conductor will be set free and 
driven from the disk. The armature a' will produce a corresponding 
but reverse effect on the conductor C ; so that this conductor will be 
charged negatively, and C positively. If, then, these conductors be 
brought near each other, a spark will pass between them. But if. with- 
out discharging them in this manner, we suddenly reverse the position 
of the glass disk intervening between the combs and the armatures, the 
negative accumulated electricity which was drawn out of C by a will 
be brought opposite to a' by which it will be repelled from the plate and 
driven to join the negative charge already accumulated in C. And 
simultaneously, the positive electricity which a' had drawn from C 
upon the disk, will be brought into a position in front of a, by which it 
will be driven into the conductor 0. 

It is further to be considered that the effect of the original charge in 
drawing negative electricity out of C can only be proportioned to the 
strength of the charge. When, therefore, by rotation, the disk has rid 
itself of these first charges drawn to it by the inductive influence of the 
armatures upon the conductors, the same influence suffices to draw fresh 
charges of the same kind as the first from the same conductors : and thus, 
the rotation continuing, the accumulation goes on. 



ELECTRICITY STATIC INDUCTION APPARATUS. 553 

It remains to be considered how the second armature becomes neg- 
atively charged, when only a positive charge is communicated to the 
first. There is no difficulty in understanding this, if we suppose the 
conductors and C to be in communication in the first instant. The 
armature a, charged positively, not only draws the negative electricity 
of through the comb-points down to the plate, but it drives the pos- 
itive electricity of and of the plate also to the opposite extremity of 
that conductor. This opposite end, when and C communicate, is vir- 
tually the comb opposite a'. The positive electricity of and C there- 
fore tends to flow out of the comb-teeth to the plate, and this electricity, 
accumulating there, induces a negative condition of the armature a'. 
The paper points attached to the armature facilitate the assuming of this 
electrical state, and discharge some positive electricity which the pres- 
ence of the similar electricity upon the disk causes to diffuse itself in 
the air. 

If there is no preliminary contact of C and C, more time will be con- 
sumed in bringing the machine to activity. In this case the negative 
electricity drawn out of by a comes, as it approaches <x', under the 
influence of the paper points connected with the armature. The repul- 
sive force which it exerts on the negative electricity of the oppo- 
site side of the disk, and its attraction for the positive electricity in a', 
cause an exchange through the paper points between the armature and 
the plate, before the comb opposite a' can act. Thus there will begin to 
accumulate upon a' a negative charge, which will slowly increase. 

Mr. Holtz thought it necessary to shield the rotating disk by the fixed 
disk, all over its surface, except where the armatures are placed. His 
impression was that the charges carried by the revolving disk are dis- 
guised by the influence of the fixed disk, and set free only when they 
come opposite to the openings, or windoivs ; and it was his opinion that 
this construction is necessary to secure transportation without loss. 
Our American constructors, however, do not employ a fixed disk, but 
substitute instead of it as many wedge-shaped or sectoral plates of glass 
as there are armatures to sustain, and give to these only breadth enough 
to afford the necessary strength. In this construction the transported 
charges on the disk are left without any such supposed protection for 
the greater part of the course. The modification here described does 
not seem to be attended with any sensible disadvantage. It is represented 
in the accompanying figure (Fig. 118) taken from a machine constructed 
by the Messrs. Chester of New York. 

CHESTER'S HOLTZ MACHINE. 

The distance at which the revolving disk is placed from the fixed plate 
is as small as it can be conveniently made, say one-tenth of an inch. 
The paper armatures cover the whole edge of the " window," and extend 
a little on the inner side ; but their greatest breadth is on the outside. 
The number of turns given to the disk per second is about the same as 



554 



PARIS UNIVERSAL EXPOSITION. 



stated above in speaking of Topler's machine; that is to say, fifteen or 
twenty to the second. In the machine as represented in Fig. 117 there 
are but two " windows" and two sets of combs. Four windows and four 



Fig. 118. 




Chester's Holtz Machine. 

combs are employed, with an increase of the quantity generated, but 
with a diminution, diameters of plates being equal, of striking distance. 
A tweuty-inch plate with four sets of combs will charge a Leyden jar of 
one hundred and sixty square inches in less than a second. 

A curious modification of the Holtz machine, devised by the inventor 
himself, and constructed by Mr. Bohrbeck, of Berlin, by whom it was 
exhibited in the Exposition, consists of a pair of rotating disks of glass. 
turning with great velocity in opposite directions, and without any ••win- 
dows." At the extremities of two diameters, at right angles to each 
other, are placed four combs, opposed to the surfaces of the revolving 
plates, and united by pairs to form two poles. This contrivance was 
not seen in operation, and nothing is known of its efficiency. 

BER.TSCH'S ELECTROSTATIC INDUCTION MACHINE. 

The machine of Mr. Bertsch, which is the latest of these induction 
machines, is also the simplest. It consists of, first, a thin disk of glass to 
be rapidly rotated, as in the case of the Holtz machine : second, a plate 



DYNAMIC ELECTEICITY. 555 

of ebonite, to serve as the exciter of electricity by induction; third, two 
sets of combs with their associated conductors. The ebonite plate is 
excited by friction with fur or silk, and then put in place opposite the 
lower limb of the plate, and as near to it as it can be placed conveniently. 
One of the combs is immediately opposite to this plate ; the other, 180° 
from this. The excited plate, excited, we will suppose, negatively, draws 
the positive electricity of the lower conductor to the disk through the 
comb-teeth, and this electricity, in the rotation of the disk, is discharged 
through the opposite set of comb-teeth upon the upper conductor. Thus 
the theory of this machine is simply that of a continuous electrophorus. 
In its construction it is much simpler and less liable to derangement 
than those of either Holtz or Topler : it is little inferior to them in its 
effects in any respect, and for some uses it is superior. 

The effects of this machine are practically heightened by the introduc- 
tion, into the construction of the conductors connected with the combs, 
of condensers, which, by suitable connection between the two, make of 
these conductors a sort of masked Leyden jar. The intensity of the dis- 
charges, as well as the quantity retained in the conductors, is thus much 
increased. 

A Bertsch machine of twenty inches diameter, two exciting plates and 
four combs, will furnish sparks four to eight inches long, and eight or ten 
in number per second. It will charge a battery of twenty square feet of 
surface in from one-half to three-quarters of a minute. 

DYNAMIC ELECTRICITY. 

Dynamic electricity is now applied to so large a variety of purposes, 
that every improvement in batteries, whether as it respects their power, 
or permanence, or economy, is a matter of great interest. The batteries 
of Grove and Bunsen have not been surpassed in energy, and probably 
will not be ; but they evolve fumes which render their presence offensive, 
a disadvantage which necessitates that they should be shut up in closed 
chambers with special arrangements for ventilation. Moreover, though 
they are sensibly constant in action while the acids are fresh, the action 
must fall off as these liquids are exhausted, and they require to be charged 
anew sufficiently often to make their maintenance troublesome. 

For very many purposes, a current of low intensity steadily sustained 
is of much greater importance than a more powerful one of less duration. 
This is true in all the operations of galvanoplasty and in the apparatus 
of electric horology ; and it has even been found to be true of the Atlantic 
telegraph. The attention of electricians has therefore been specially 
turned, in recent years, to the construction of batteries capable of long- 
continued action, and which can be left to themselves without apprehen- 
sion of their failure for periods of many months. 

HYDROELECTRIC BATTERIES. 

The sustaining battery of Daniell, invented in 1836, was the first 
which possessed to any degree the character of permanence. In its 



556 PARIS UNIVERSAL EXPOSITION. 

original form it presented some practical inconveniences which do not 
exist in the modifications which it has since undergone. But even in its 
original and comparatively imperfect shape, it was a gift of inappreciable 
value to electrical science and to all its applications ; and it first made 
practially feasible the project, which was before but a tantalizing and 
doubtful possibility, the electric telegraph. 

DanielFs battery consisted of a zinc and a copper element, each immersed 
in a separate saline solution ; the solutions being prevented from ming- 
ling by the interposition of a porous diaphragm. Leather or some kind 
of animal membrane was originally employed as the material of the 
diaphragm. These substances were subsequently replaced by porous 
earthenware. All forms of diaphragm are liable to some objections. 
If of membrane, they are not durable ; if of pottery, they are fragile ; 
and both kinds become sooner or later covered in parts with precipitated 
copper. 

The unsatisfactory action and speedy loss of power of the battery 
which had been up to this time in use arose from the accumulation of 
hydrogen in minute bubbles upon the negative plate, obstructing free con- 
tact with the liquid, and to some extent polarizing the battery in the 
opposite direction. This evil was overcome at a later period by an 
ingenious expedient originated by Mr. Alfred Smee, of London, which 
consisted in replacing the copper element of the battery by a platinum 
plate coated with platinum electrically precipitated. The bubbles fail to 
adhere to the rough surface of the precipitated metal, and the obstruc- 
tion above spoken of no longer occurs. Though Mr. Smee employed 
plates of platinum in his original arrangements, less costly metals serve 
equally well, when platinized on their surfaces. Silver has been gen- 
erally substituted for the platinum of the plates ; and as the thickness 
may be very small, the expense is not considerable. More recently, iron 
has been also used for the same purpose, with satisfactory results. 

In the Austrian section of the Exposition there was exhibited a Smee 
battery, by Colonel Ebner, of the imperial engineers, in which platinized 
lead had been employed as the negative element. The cups of this bat- 
tery are large, measuring about twenty inches high by five inches in 
diameter. The lead is in the form of a hollow cylinder smaller in dia- 
meter than the cup, and supported by a flange which rests on the top. It 
is immersed to the depth of only six or seven inches, the design of the 
great capacity of the cup being to protract the action of the battery, by 
allowing a large quantity of the exciting liquid to be introduced. The 
top of the cup is covered by a disk of porcelain, with perforations to allow 
the electrodes to pass through, and to permit the introduction of the 
liquid after the apparatus has been arranged. A stopper is adapted to 
the orifice intended for this latter purpose, to prevent as far as possible 
evaporation. The positive element, which is formed of zinc, is nor 
moulded into any particular shape, but is introduced in fragments into 
a small bucket of porcelain with large openings in its sides for the free 



DYNAMIC ELECTRICITY, VARIOUS FORMS OF BATTERIES. 557 

admission of the liquid. The zinc is amalgamated, and the bottom of 
the bucket contains an excess of mercury by which the amalgamation is 
maintained. This bucket is suspended in the middle of the hollow cyl- 
inder of platinized lead, by means of a hollow stem which extends to the 
bottom of the bucket, and rising through the porcelain cover is sustained 
by a flange. This hollow stem gives passage to the electrode on the 
side of the zinc. The exciting liquid is weak sulphuric acid. Apart 
from the peculiarities of arrangement, and the large relative size of the 
cups, there is nothing novel in this battery except the platinized lead. 
It is said to be in use in Austrian telegraph offices. 

The evil above spoken of which Mr. Smee's contrivance was designed 
to obviate, i. e., the accumulation of hydrogen upon the negative metal, 
was overcome in the battery of Daniell by the deconqjosition of the salt 
in contact with that element and the union of the oxygen of its base with 
this hydrogen to form water. The salt on the positive side is not ne- 
cessary to the action of the battery, but promotes its activity, by increas- 
ing the conducting power of the liquid. In the nitric acid batteries of 
Grove and Bunsen, the hydrogen is suppressed by oxidation in a man- 
ner analogous to that above described. Daniell's battery is simplified 
by employing but a single saline solution, this being kept constantly 
saturated on the side of the negative element, while on the positive side 
the liquid is nearly pure water. 

A simple but very permanent battery of low intensity constructed on 
this principle was introduced some years since by Mr. M. G-. Farmer, of 
Boston, and was employed, as it probably still is, in connection with the 
system of electric fire-alarms in that city. This battery consists, first, of 
an oval-shaped copper vessel, which constitutes the negative element 
and which is nearly filled with a saturated solution of sulphate of cop- 
per. Within this, at one end of the oval, is placed a porous cup, and 
within this a smaller porous cup designed to receive a cylinder of amal- 
gamated zinc, which forms the positive element. The zinc being in 
place, pure water is poured into the smaller porous cup and a weak solu- 
tion of sulphate of copper into the larger. The saturation of the liquid 
in the outer or copper vessel is maintained by placing a third porous cup 
in the opposite end of the oval, filled with crystals of sulphate of copper. 
As these crystals are gradually dissolved, the supply in the cup is from 
time to time replenished. No other attention is necessary except to see 
that the water does not fall too low. These matters being properly pro- 
vided for, the battery will continue to act without sensible variation of 
energy for many months. Three cells of this battery, employed by 
the writer to drive an electric clock, performed satisfactorily for six 
months or upwards without change. The power was a good deal in excess 
of the necessity of the case. A single cell sufficed to drive the clock. 
The others were added for security. 

Quite analogous to this, but essentially different in arrangement, is the 
battery devised by the Eev. Father Secchi, of Eome, and exhibited in 



000 PARIS UNIVERSAL EXPOSITION. 

the Exposition in connection with his interesting meteorographe elsewhere 
described. In this battery, a hollow cylinder of copper, notched at the 
bottom to permit a free communication between the liquid within and 
without, is placed upright in the middle of a deep cup of glass or earthen- 
ware, and the bottom of the cup is covered with crystals of sulphate of 
copper. On the top of the salt is formed a stratum of bibulous paper 
outside of the copper, the paper being cut into rings having dimensions 
corresponding to the section of the annular space. Then follows a stra- 
tum of sand, on which rests a hollow cylinder of zinc surrounding the 
copper. The interior of the copper cylinder is filled with powdered sul- 
phate, and the filling of the remaining space on both sides of the zinc is 
completed with sand. The whole is then moistened with water. This 
battery is very constant. According to the statements of Father Secchi, 
it acts for an entire year, requiring no other attention than the occa- 
sional addition of water and a small quantity of sulphate of copper. 

The batteries of Mr. Oallaud, of Mantes, and of Mr. Minotto, of Turin, 
are very similar to that of Father Secchi. In the first, a plate of cop- 
per in a horizontal position is imbedded in a stratum of crystallized 
sulphate of copper at the bottom of the cup. To this is soldered a con- 
ducting wire protected by a coating of gutta-percha. A saturated solu- 
tion of sulphate of copper is poured into the cup until the stratum of 
salt is covered, and the remainder of the cup is filled with pure water. 
In the upper portion of the cup is suspended a hollow cylinder of zinc, 
which rests upon the top by a flange. The second differs from this in 
having a stratum of sand over the bed of salt at the bottom of the cup, 
and using the sulphate not in crystals but in powder. These batteries 
require to be charged anew as soon as the sulphate is exhausted, and in 
this respect are less favorable to long continued action than that of 
Father Secchi. 

The sulphate of mercury battery of Professor Marie-Davy is a carbon 
battery, in which the bisulphate of mercury occupies the place of the 
nitric acid of the battery of Bunsen. This salt is nearly insoluble, and 
it is therefore reduced to powder and made into a paste by trituration 
in two or three times its volume of water, the excess of water being 
afterwards withdrawn. The electric action deoxidizes the mercury, 
which subsides to the bottom of the cup, while the sulphuric acid 
attacks the zinc and forms a sulphate. 

Mr. Leclanche, of Paris, exhibited in the Exposition an ingenious form 
of battery, which, as stated by the Abbe Moigno in -Les Mondesi has 
been introduced into several telegraphic offices on the continent of 
Europe. This is also a carbon battery in which the peroxide of man- 
ganese takes the place of the nitric acid. In the earlier trials of this 
battery the manganese was introduced in fragments into the porous cup 
containing the carbon element. Mr. Leclanche has since found it better 
to grind it to powder and to employ a paste consisting of a mixture of 
this powder and carbon. The natural crystalline peroxide is the only 



BICHROMATE BATTERY THOMSEN's POLARIZATION BATTERY. 559 

kind employed. The positive element is a stout rod of amalgamated 
zinc, and the exciting liquid is a concentrated solution of sal ammoniac. 
In connection with these improved forms of the carbon battery may 
properly be mentioned the modification introduced a few \ ears since by 
Professor Bunsen, consisting in the substitution for nitric acid, on the side 
of the negative element, of a solution of bichromate of potassa. On the 
zinc side the liquid is dilute sulphuric acid, as usual. This battery per- 
forms very well for a time ; but, in consequence of the precipitation of 
the sesquioxide of chromium upon the zinc, it gradually loses power. 
Another modification consists in dispensing with the porous cup or 
diaphragm and using the two liquids in mixture. In this form the 
elements are combined by securing each plate of carbon between two 
plates of zinc, the whole being attached to a supporting disk of hard 
caoutchouc. The same difficulty occurs in this case as in the other ; but 
it has been shown by Mr. Ruhmkorff that, if the carbons are four or 
five times as long as the zincs, the deposit of the oxide is very much 
retarded. 

A remarkable battery, called by its inventor, Professor Jules Thomsen, 
of Copenhagen, a polarization battery, was exhibited in the Danish section. 
Fifty-two plates of platinum are immersed in dilute sulphuric acid, and 
these are successively brought into contact, by pairs, with the poles of a 
single cell of Daniell. In consequence of these contacts the plates 
become covered, by the decomposition of water, with oxygen on one side 
and hydrogen on the other. This polarization gives rise to a powerful 
current in the platinum combination 5 and this is maintained nearly 
constant when the contacts succeed each other rapidly and regularly. 
To secure this object, the electrodes of the exciting battery are kept in 
rotation by means of an electro-magnetic motor. Professor Thomsen states 
that the fifty cells which correspond to the fifty-two platinum plates 
produce a current equal in intensity to that of seventy-three elements 
of Daniell. 

In an experiment made in the Exposition with this battery, by Mr. 
Sabine, of the British commission, with two Bunsen elements as the 
exciting battery, and thirty-eight rotations of the commutator per 
minute, producing nineteen hundred separate polarizing charges in the 
same time, the electro-motive force was equal to that of seventy DanielFs 
elements. This is considerably less than is claimed by Professor Thomsen ; 
but it is possible that a greater or less velocity of rotation might have 
produced a better result. 

THERMO-ELECTRIC BATTERIES. 

Thermo-electric batteries were exhibited in the United States section 
by Farmer, in the Austrian by Marcus, and in the French by Ruhm- 
korff. The battery of Farmer consists of strips of copper and blocks 
of a kind of alloy of which the nature is not known, arranged alter- 
nately. The alloy is in wedge-shaped masses two inches in length and 
one in depth, with a breadth of half an inch at one end and one-quarter 



560 PARIS UNIVERSAL EXPOSITION. 

at the other. This form was adopted to permit the convenient arrange- 
ment of the elements in a ring, the broad extremities being placed 
outermost. The strips of copper are introduced between these sectoral 
blocks and soldered to them by their opposite extremities alternately. 
Insulation between the metals is effected by the interposition of plates 
of mica. Heat is applied to the inner extremities, a circular gas burner 
being employed as the source. It is stated that thirty-six elements of 
this battery are equal to one of Grove's. The internal resistance is 
equivalent to that of sixty feet of copper wire Xo. 18. Some better 
arrangements appear to be necessary to maintain the depression of tem- 
perature in the outer extremities of the elements. 

The battery of Professor S. Marcus, of Vienna, is composed of elements 
both of which are alloys. The positive element consists of ten parts by 
weight of copper, six of zinc, and six of nickel ; the negative of twelve 
parts of antimony, five of zinc, and one of bismuth. These are con- 
nected in such a manner that the combination bears some resemblance 
to the roof of a house, the rafters, or separate elements, being soldered 
by their alternate extremities, and separated by a slight space with no 
intervening insulation. The system stands in the position of a roof, the 
lower edges which form the eaves being immersed in cold water. Heat 
is applied by means of a spirit lamp with a long wick extending beneath 
the roof from end to end of the system, and loss of heat by radiation is 
prevented by a screen or cover of earthenware, in the form of an inverted 
trough. One hundred and twenty-five pairs of this battery generate 
twenty-five cubic centimeters of mixed gases (nearly six and a half 
cubic inches) per minute. Sixty -five pairs are sufficient to develop a 
lifting force in an electro-magnet of twenty-five to fifty kilograms. 

Becquerel's thermo-electric battery dates from 1865. It was discov- 
ered by this gentleman, in the course of his investigations, that arti- 
ficial sulphuret of copper, when heated to two hundred or three hun- 
dred degrees centigrade, is strongly positive, and that a couple formed 
of this substance and metallic copper has nearly ten times the electro- 
motive force of the ordinary copper and bismuth couple. This is 
remarkable, as the native sulphuret is strongly negative. The metal, 
however, employed in this battery along with the artificial sulphuret is 
not copper, but is an alloy of ninety parts of copper with ten of nickel, 
such as is commonly known by the name of German silver. The 
arrangement of the elements in the battery considerably resembles that 
of Marcus. Heat is applied by a gas burner, which, in the battery 
exhibited, consisted of a tube with perforations on its upper side extend- 
ing along beneath the central line of junction of the elements. The 
outer extremities of the elements, as in the case of the battery pre- 
viously described, are immersed in cold water. Eight or nine pairs of 
these elements are esteemed by Mr. Becquerel to be equal to one of Dan- 
ielle. With fifty couples an electro-magnet has beeu made to sustain a 
weight of one hundred kilograms. The intensity of the current is very 
great, and also the internal resistance. 



INDUCT rON THE ARTIFICIAL AURORA. 561 

ELECTRO-MAGNETS AND INDUCTION COILS. 

An enormous electro-magnet, designed for investigations of diamag- 
netisin, was exhibited by Mr. Ruhinkorff. The weight of the soft iron 
core of this magnet is no less than four hundred kilograms, (nearly 
nine hundred pounds,) and that of the enveloping wire is quite as 
great. Its lifting power is said to be fifteen thousand kilograms. The 
secondary spark produced in breaking the exciting current of this mag- 
net is so powerful, that to the observer, the conductor itself seems to be 
bursting into flame. A rotation of the plane of polarization of a ray of 
light may be obtained in repeating with this magnet Faraday's cele- 
brated experiment, amounting to no less than forty degrees. 

A large electro-magnet which was exhibited by Professor Hamar, of 
Pesth, presents the peculiarity that the ordinary envelope of insulated 
wire is replaced by disks of copper. To what extent the power is 
increased or diminished by this construction, was not ascertained. 

A very magnificent induction coil, the largest probably ever made, 
formed a part of Mr. Kuhmkorff's splendid exposition. Its height as it 
stands is seventy-five centimeters, or thirty inches. The length of the 
wire in the primary circuit is fifty meters 5 its diameter is two and three 
quarter millimeters, forming two layers upon the core. The wire of the 
secondary circuit is one hundred and fifty kilometers (ninety-three 
miles) long, and one-ninth of a millimeter in diameter. This wire is 
wound in disks — a mode of winding which, it is believed, originated 
with Mr. E. S. Ritchie, of Boston, in 1856, and makes eighty-five turns 
in each disk. The coil is accompanied by a Foucault circuit-breaker, 
and gives a spark in the air of fifty centimeters (twenty inches) in 
length. In an exhausted tube the spark passes ten meters. It charges 
instantaneously a battery of four square meters of coated surface. 

Geissler's tubes were exhibited in great variety and beauty by Messrs. 
Ruhmkorff, Alvergniat, Gaiffe, and Seguy ; and also at a late period by 
Geissler himself. Though there were many novel patterns, the appa- 
ratus itself presented no points of novelty, unless an exception be made 
in the case of the miners' electric lamps, which are simply Geissler's 
tubes adapted to a useful and an important purj)ose. These lamps are 
recommended by their entire safety, and by the fact that they require 
no trimming. 

DE LA RIVE'S AURORA BOREALIS. 

The most interesting of all the forms of apparatus exhibited, designed 
to illustrate the relations of light to electricity, was a combination pre- 
sented by the society for the construction of physical apparatus of 
Geneva, and invented by Mr. De La Rive, in which are reproduced in 
miniature all the most striking phenomena of the aurora borealis. This 
apparatus consists of a hollow sphere of wood, designed to represent 
the earth, which contains an electro-magnet occupying the position of 
36 i A 



562 



PAEIS UNIVERSAL EXPOSITION. 




the axis, while the polar regions are crowned by two bell-glasses fixed 

air-tight to the sphere. The arrangement is shown in Fig. 119, in which 

Fig. 119. B is the sphere, 

supported on a 
foot, and C C are 
the bell-glasses. 
These bells are 
attached to the 
sphere by two 
rings of metal in- 
dicated by the let- 
ters / /'. At a 
and b are stop- 
cocks, which per- 

De la Rive's Auroral Apparatus. mit the bells to 

be exhausted by communication with an air-pump. The electro-magnet 
is concealed within the sphere, the soft iron core reaching only to the 
plane of the circles/ and f ; but it is lengthened by means of two soft 
iron cylinders of similar cross-section, which are insulated from it by 
interposed plates of mica. These- cylinders, marked P and P', are in 
metallic communication with the corresponding rings / and /'. From 
each of the two stop-cocks proceeds a stirrup-shaped wire, e, which car- 
ries a ring, A, of brass gilded. The sphere is surrounded by an equa- 
torial circle of brass, which carries a connecting screw at B. In the 
meridional direction from one of the rings / to the other, there passes 
over the top of the globe an imperfectly conducting band, formed of a 
composition of black lead and sulphur. This is not in immediate con- 
tact with the rings, but may be connected with them by means of two 
springs or switches of brass, operated by buttons of ivory at m and n. 
On the under side there is another band made of thick paste-board, 
which, when dry, is non-conducting, but which is converted into an 
imperfect conductor by being moistened with a saline solution. Several 
bindiug screws v v are attached to the superior meridian, for the pur- 
pose of connecting a galvanometer with the apparatus, in order to illus- 
trate the effects of the aurora upon the magnetic needle. 

In experimenting with this apparatus, the bell-glasses are first ex- 
hausted, after which communication is made from the binding screw B 
to the negative electrode of a Buhmkorff coil, while the positive elec- 
trode has a double connection, as shown, with the stop-cocks a and 6. 
A continuous discharge is kept up from the coil by means of an auto- 
matic circuit breaker. The luminous jet then makes its appearance in 
the bells as marked by the arrows. The light is equal in the two bells 
only on condition that the resistance in the two circuits is equal, a case 
which rarely occurs. It may be thrown into one or the other at 
pleasure by opening and closing alternately the interrupters at m and n. 
In this state of things, if the electro-magnet within the sphere be put 



DE LA RIVE'S AURORAL APPARATUS. 563 

into communication with its battery, the jet spreads itself out and takes 
at once the form of a luminous shell. 

Iu illustrating the influence of vapors upon the aspects of the light, 
the connections are differently arranged. The positive electrode of the 
coil is connected with the stop-cock a, the ring / with the stop-cock b, 
and the ring /' with the negative electrode. The exhaustion of the 
bell-glasses is carried as far and is made as equal as possible. On pass- 
ing the induced current of the coil, and exciting the electro-magnet, the 
jet will appear in both bells, and will assume a motion of rotation 
around the poles P P', changing its direction whenever the current is 
reversed. The jet appears sometimes single and sometimes divided into 
several minor streams. If a minute quantity of water be now admitted 
to one of the bells, which may be done by means of a stop-cock pro- 
vided for the purpose, the effect of the vapor thus produced upon the 
appearance of the light is instantaneous, and recalls the well known 
form and movements of the columnar aurora. 

The influence exerted by the aurora upon the magnetic needle is illus- 
trated by connecting the communicating wires of a galvanometer with 
any two of the binding screws v v during the progress of the exj>eri- 
ment. The galvanometer is placed so far from the apparatus as to be 
beyond the reach of any direct influence from the electro-magnet ; but 
as the superior meridian is imperfectly conducting, the derived current 
from / to /' will traverse the coil rather than follow the more direct 
route, and the needle will be deflected, thus showing artificially the 
effect which the natural aurora always produces. By interrupting the 
upper current at m or n, and moistening with the saline solution the 
pasteboard meridian band of the lower hemisphere, similar effects may 
be shown on that side also. 

ELECTRO-CHRONOSCOPES. 

The application of electricity to the determination of minute intervals 
of time has contributed materially to the exactness of results in a num- 
ber of important departments of scientific observation. Illustrations 
have already been given of the manner in which experimental investi- 
gations in acoustics have been facilitated by electrical methods of main- 
taining vibrations. In astronomy the introduction of the electrical 
method of recording observations has been a source of still higher 
advantage. Thirty years ago one second was the smallest interval of 
time for which astronomers possessed an exact instrumental measure. 
Intervals less than seconds were merely estimated; that is to say, guessed 
at, the judgment of the observer being assisted by the apparent motion 
of the object observed across the lines of his instrument. The intro- 
duction into astronomical observatories of the electro-chronograph first 
suggested by Professor Locke, of Cincinnati, constituted an important 
era in the history of practical astronomy. 



564 PARIS UNIVERSAL EXPOSITION. 

The study of the flight of projectiles is another branch of experimental 
inquiry which has been greatly aided by electro-chronographic methods. 
The earliest observations on the velocity of cannon balls were made by 
means of mechanical contrivances which, though exceedingly rude, were 
for fully a century the only means known of attaining or approximating 
to the knowledge sought. These were the ballistic pendulum of Eobins, 
and the gun-pendulum of Eumford. 

To Professor Wheatstone belongs the credit of having first suggested, 
in 1840, the use of electricity to mark the instants of time in which a 
projectile passes in its flight two determinate points, and of thus deduc- 
ing the mean velocity with which it describes that portion of its trajec- 
tory. His apparatus consisted of a revolving cylinder, upon which 
rested lightly a tracer, describing, as the cylinder turned, a mark upon 
its surface. When the instrument was prepared for experiment, this 
tracer was retracted by the influence of an electro-magnet. Two wire 
targets, or screens, were placed at suitable distances before the gun, and 
were so connected with the electrical circuit operating upon the magnet 
that, as the projectile passed the first, this circuit was broken, and as it 
passed the second, the circuit was re-established. With the rupture of 
the circuit the tracer fell upon the cylinder, and it was instantly with- 
drawn again on the renewal of the current. The velocity of rotation of 
the cylinder being known, the length of the line traced during the brief 
interval between these two incidents became an indirect measure of the 
velocity of the projectile. 

In 1843, Professor Henry, of Princeton, now Secretary of the Smith- 
sonian Institution, a physicist whose name is inseparably associated 
with the history of electrical discovery, presented to the American Philo- 
sophical Society a paper in which he proposed to mark on the surface 
of a revolving cylinder, by means of the intense secondary spark of an 
induction coil, the instants in which an electric circuit is ruptured by a 
projectile. This was the first suggestion of an expedient which many 
inventors have since adopted, and which is employed in the most remark- 
able of the electro-chronoscopes exhibited in the Exposition, that of 
Captain F. P. E. Schultz, of the imperial artillery of France. 

The first electro-chronoscope proper, however, in the order of inven- 
tion, was that of Captain Navez, of the Belgian artillery, called by him, 
from the peculiarity of its construction, the electro-ballistic pendulum. 
This is, as its name implies, a pendulum, having a length of only a few 
inches, and traversing in its swing a graduated semicircular are having 
its center at the point of suspension. The pendulum carries with it an 
index, which may be stopped in the descent at any point of the scale, by 
the action of an electro-magnet behind the instrument, without arresting 
the pendulum itself. When prepared for experiment the pendulum is 
raised to the horizontal position, the index being coincident with it. ami is 
held there by another electro-magnet. As the projectile breaks the wire 
of the first screen the pendulum falls. Before the swing is completed the 



ELECTRO-CHRONOSCOPES. 565 

the second wire will be broken ; and this rupture of circuit determines the 
action of the electro-magnet which stops the index. Here, however, the 
action of the instrument is a little complicated. The immediate effect of 
the breaking of the second wire is merely to drop a little weight. It is 
the fall of this weight which closes the circuit of the second magnet and 
stops the index. The division on the scale at which the index is stopped 
will give, from the known law of acceleration of the pendulum, the time 
which has elapsed from the commencement of the swing. But this time 
embraces not only that occupied by the projectile in passing from screen 
to screen, but in addition to this the time of the weight in falling. The 
latter term, however, is a constant, and it is eliminated by means of a 
preliminary experimental determination of its value, made by breaking 
the circuits of both magnets at once, and so dropping both pendulum 
and weight in the same instant. 

The pendulum of Captain Navez did much to advance the science of 
ballistics; but it was objected to it that the release of a body suspended 
by an electro-magnet is not instantaneous; so that neither the pendu- 
lum nor the weight begin to fall in the instant of the rupture of the cir- 
cuits of their respective magnets. It was further alleged as an objection 
that it is too delicate and too complicated for general use. 

In 1859, Major (now Lieutenant Colonel) James G. Benton, of the ord- 
nance department of the United States army, constructed an electro- 
ballistic pendulum of a simpler description. In this there are two equal 
pendulums suspended one behind the other from the same center of 
motion, and traversing also, as in the case of that just described, a semi- 
circular divided arc. The pendulum nearest the arc has a movable 
point directed toward the arc; and the outer one carries a projection 
suited to drive this point against the limb as the two pass each other in 
the swing. When the instrument is prepared for use, the two pendu- 
lums are brought both to the horizontal position, and suspended by 
electro-magnets at opposite extremities of the semicircle. A paper is 
also attached to the limb to receive the mark of the point. The pendu- 
lums are successively released by the rupture of the circuits of the mag- 
nets sustaining them as the projectile passes the two screens; and the 
mark left at the point of meeting serves to ascertain the difference 
between the times of release. In order that the indications of this 
instrument may be trustworthy, it is necessary to be assured that, wheu 
the two pendulums are simultaneously released, they meet accurately in 
the middle of the limb, or at the point of lowest descent. It has been 
objected to Captaiu Benton's pendulum, as to that of Captain Kavez, 
that the retardation of the moments of release on account of the per- 
sistency of magnetism in the soft iron cores of the electro-magnets, ren- 
ders the indications in a measure uncertain; but the instrument has 
performed remarkably well in experiments made with it by ordnance 
officers in the United States service. 

The secondary spark from the induction coil originally suggested, as 



566 PARIS UNIVERSAL EXPOSITION. 

above mentioned, by Professor Henry, for this use, is believed to have 
been first actually introduced as a substitute for the mechanical mode 
of marking, by Captain Martin de Brettes, of the French artillery, in 
1858. At an earlier period (1854) Captain Siemens, of the Prussian ser- 
vice, had proposed, for the same purpose, the spark of the Ley den jar. 
Captain Siemens employed in his experiments a polished steel cylinder 
rotating uniformly, on the surface of which the spark in passing produces 
a visible tarnish. Captain de Brettes at first applied his method to a 
pendulum, which discharged sparks upon the graduated limb before 
which it swung. He subsequently employed a body falling directly, in 
guides, in front of a plane surface, the sparks passing to this surface 
from the falling body in different parts of its vertical trajectory; and he 
finally adopted the revolving cylinder in preference to either of the 
other expedients, as permitting a greater protraction of the experiment. 
The cylinder is, in fact, indispensable, in case a projectile is to be followed 
up throughout its entire trajectory, or even for any considerable part of 
it; since the duration of the swing of the pendulum, or of the direct fall 
of a body through any distance admissible into the apparatus, can only 
amount to a fraction of a second. A cylinder, however, revolving on a 
helical axis, which advances it slightly in the direction of its length at 
every revolution, permits a continuation of the observation through any 
desirable length of time. 

The form of chronoscope upon which Captain de Brettes has finally 
settled down is exhibited in the Exposition by Mr. E. Hardy, of Paris, 
by whom it was constructed under his direction. He still inscribes his 
record on a cylinder, but he chooses that the cylinder shall remain fixed, 
while the marker revolves around it. The cylinder has a vertical posi- 
tion, and is divided on its cylindrical surface by lines parallel to the 
axis into one thousand equal parts. The marker travels round it three 
times per second. In the mean time a strong mechanism of clock-work 
causes the cylinder gradually to descend, while the marker moves always 
in the same horizontal plane, and thus the marks made in different revo- 
lutions are kept distinct from each other. The revolution of the marker 
is produced by a conical pendulum which surmounts the whole apparatus. 
This is driven by clock-work and requires no escapement, the revolution. 
which is completed in one second, being entirely uniform. The driver 
which maintains the motion of the pendulum might also, if thought 
expedient, carry the marker ; but an intermediate gearing is interposed 
in order to increase the velocity and produce three rotations per second 
instead of one. It follows, of course, that the arm carrying the marker 
must bend at right angles and descend vertically at least far enough to 
deliver its sparks at the lower margin of the cylinder Avken that is ar 
its highest point. 

In the earlier experiments of Captain de Brettes with the Ruhmkorff 
coil he employed paper as the material on which to receive the sparks. 
But the punctures made by the spark in paper are so minute and so 



ELECTRO CHRONOSCOPES. 567 

difficult to find, that, like Captain Siemens, he resorted subsequently to 
metallic surfaces. The cylinder in the instrument actually exhibited is 
made of bronze, and is silvered by galvanism on its cylindrical surface. 
Silver has the advantage over steel, which was the metal used by Captain 
Siemens, in being much more easily repolished after being spotted by 
the sparks. No information was obtained as to the performance of this 
instrument. 

In the Exposition are exhibited electro-chronoscopic instruments by 
three inventors, besides Captain de Brettes. The Belgian section con- 
tains several very ingenious forms of this apparatus, by Professor M. 
Gloesener, of Liege. In one of these a plane surface is made to fall 
vertically under the influence of gravity, while marking points held in 
check by electrical attraction fall on it at intervals as their circuits are 
broken. In another, the pendulum principle is adopted ; but the whole 
limb swings and the markers fall on it as in the case just described. In 
a third there is employed a uniformly rotating cylinder with several 
markers in front of it, permitting several successive marks to be made 
during the same experiment. This cylinder is governed by a Foueault 
regulator, the efficiency of which contrivance has been elsewhere men- 
tioned. A special merit of Professor Gloesener's instruments is that the 
possible error arising from persistency of magnetism, which renders the 
indications of several of the instruments above spoken of more or less 
uncertain, is entirely eliminated. Professor Gloesener's markers are not 
connected with soft-iron armatures controlled by electro-magnets, but 
they are magnetic bars of steel, surrounded by galvanic multipliers; 
that is to say, they are substantially galvanometer needles. Each one 
carries at its extremity a small hollow cone with a minute perforation 
at the summit, into which is introduced some suitable marking liquid. 
The needles start instantly when the circuits are broken, and the time 
of fall is the same for every one. This can be verified by dropping them 
all together. 

In the French section is exhibited the electro- chronoscope of Captain 
Schultz, already mentioned. In this machine a cylinder of rather large 
dimensions (one metre in circumference) covered with paper, which is 
afterwards coated with smoke as for the experiments heretofore described 
in acoustics, is designed to receive the marks made by the sparks of an 
induction coil as the projectile breaks the successive circuits. Close by 
the side of the point which delivers these sparks is a diapason carrying 
a light tracer, which rests on the cylinder and produces there, wheu the 
instrument is in operation, a continuous mark. The cylinder turns on 
a helical axis, so that if it be permitted to run while the diapason is at 
rest, the mark left by the tracer will be a uniform and smooth spiral 5 
but if the diapason be put into vibration, the spiral becomes sinuous or 
dentelated. In preparing for experiment the smooth spiral is first 
obtained, and then the instrument is set back to the original starting 
point. The diapason being provided with the electro magnetic apparatus 



568 PAEIS UNIVEKSAL EXPOSITION. 

for maintaining vibration, described in the article on acoustics in this 
report, is first excited by mechanical means. The automatic interruptor 
then immediately takes effect and continues the Aibration until the cir- 
cuit of its controlling electro- magnet is broken. As the cylinder turns, 
the sinuosities of the path described by the tracer cross the mean line 
in the middle of every simple vibration, and establish so many exact 
points of reference for the determination of time. The diapason makes 
one thousand vibrations per second and the cylinder makes three turns 
in the same time. 

There is a peculiarity in the construction of the screens used by 
Captain Schultz, which requires mention. The wires are attached at 
their upper extremities to metallic springs and hold these springs just 
out of contact with a metallic plate above them. The space of separa- 
tion is very minute, and the moment a wire is broken its spring strikes 
the plate. The rupture of the wire causes the spark to pass in the 
instrument, but the contact of the spring with the plate, which almost 
instantaneously follows, closes the circuit for the next screen, so that 
when the projectile reaches that, a second spark passes. The current 
is then closed in the same way for a third screen, and again for a 
fourth, and so on. The Schultz electro-chronoscope has been used by 
officers of the United States ordnance service with very satisfactory 
results. 

The fourth exhibitor of electro- chronoscopic apparatus is Professor 
F. Bash forth, of Woolwich, England. Professor Bashforth uses a cylin- 
der to receive the indications; but these indications are permanent 
marks made by hard points on a glazed paper covering the cylinder. 
The axis of the cylinder is vertical, and at its lower extremity it passes 
downward through the base of the apparatus, which has the form of a 
tripod. A heavy horizontal fly-wheel is attached to it here, which, when 
the instrument is to be used, is put in motion by the hand. As the 
friction is small and the mass of the fly considerable, the rotation is 
sustained for some length of time with sensible uniformity. The 
accuracy of the time measurements is not, however, dependent on the 
permanent uniformity of rotation, since marks from a clock beating 
seconds are recorded at every beat, precisely in the same manner as in 
the well-known astronomical chronograph of Bond; that is to say. a 
point, which traces in the intervals between the beats a continuous line, 
suddenly starts aside as the clock contact is made ; that is to say. at 
the end of every second. In Professor Bashforth's apparatus there are 
two markers side by side, one making a mark every second and the 
other marking at every rupture of a circuit by the projectile. The cir- 
cuits when broken are re-established in the same manner as in the Schultz 
screens. There is one further difference between the two contrivances 
last mentioned, which relates to the mechanical arrangements. In the 
Schultz instrument the cylinder advances in the direction of its length. 
In that of Professor Bashforth the cylinder has no longitudinal move- 



METEOROLOGICAL INSTRUMENTS. 569 

inent, but the markers are carried by a frame which moves vertically in 
guides, and which, by a pulley arrangement, is allowed to descend 
slowly by its own weight as the cylinder turns. The result is, as in the 
other case, that a fresh portion of the cylinder is brought under the 
markers at every revolution. 

VII.— METEOKOLOGY. 

To however greater or less a degree a scientific visitor to the Exposi- 
tion might have been disappointed in his search for interesting novel- 
ties, one fact he could not have failed to notice as evidencing remarkable 
progress in recent years, which is the singular development given by 
later observers in meteorology to apparatus designed for the automatic 
registration of the varying conditions of the atmosphere. The truth 
seems to be every day more and more distinctly recognized that the 
system of meteorological observation heretofore pursued is entirely 
inadequate to the discovery of the laws which govern atmospheric 
changes. This system has been long in operation. It has been faith- 
fully and patiently followed up at a multitude of stations scattered all 
over the surface of the habitable world. It has drawn heavily upon the 
time and strength of many able men and earnest devotees of science, 
and it has accumulated a mass of recorded observations of the humidity, 
temperature, pressure, and movements of the air so great, that it would 
seem as if it must suffice to the discovery of everything which it will 
ever be possible for man to discover in regard to the causes affecting 
these phenomena. At some of these stations the records thus gathered 
have been printed for the general use of the scientific world. At many, 
they have become so voluminous that the inquirer who desires to extract 
from them the evidence of law which they are presumed to embody, is 
embarrassed by the abundance of his material and disheartened by the 
intolerable tediousness of his task. A record, while it stands in the 
form of a succession of numbers, teaches nothing. Even the combina- 
tion of the numbers which are recorded under the present system at 
our numerous meteorological observatories, however variously and labo- 
riously made, teaches little. The mean pressure, the mean temperature, 
the mean velocity of the wind, &c, at a given hour of the day at the 
station, for the year or for the month, may be ascertained, and the 
extreme limits of the fluctuations may be detected. This may be done, 
perhaps, for several selected hours of the day. But the oscillations 
about these means cannot be clearly presented to the mind in any other 
way but by projecting all the observations into the form of curves. The 
process is inexpressibly wearisome, and the result after all is compara- 
tively valueless ; for the fluctuations of atmospheric condition are con- 
tinually going on, while our observations periodically made touch them 
only momentarily here and there at a few isolated and widely separated 
points. 

The observations of the several instruments in meteorological obser- 
vatories generally are made four times a day; in some perhaps, but 



570 PARIS UNIVERSAL EXPOSITION. 

certainly not in many, more frequently. Bnt even if they were made 
hourly they would still be discontinuous, and would still be recorded in 
the numerical form; a form which, however conducive to the exactness 
of absolute determinations or convenient for the uses of calculation, con- 
veys to the mind no clear conception of the nature of the changes which 
are proceeding, and no clue to the laws which govern them. The 
system of meteorological record heretofore almost exclusively pursued 
is defective, therefore, in this, that as to time, it is limited to observations 
which are intermittent and periodical ; and as to form, it embraces only 
the scale readings at the moments of observation of the several instru- 
ments set down in numbers. 

A system is therefore needed in which the registration of the instru- 
mental indications shall go on incessantly, and shall furnish a record of 
the fluctuations of atmospheric condition which shall be absolutely 
unbroken; while at the same time these fluctuations are expressed 
explicitly and graphically in the form of curves, rather than by obscure 
implication in columns of numbers. Such a system can only, of course, 
be carried into effect by means of automatic instrumental registration. 

The extent to which this necessity is at present recognized is made 
evident by the number and variety of forms of self-registering apparatus 
for the observations of meteorology which have been brought forward in 
the Exposition of 1867. All of these instruments are ingenious ; many 
of them are admirable. Their general introduction into observatories 
will do much to remove from the science of meteorology the reproach 
which has long rested upon it of being a barren science — a science which 
exacts more of its votaries than any other, and returns them less. 

But there is a second defect of the system of meteorological observa- 
tion and record in common use, against which the ingenious inventors 
whose instruments are here exhibited have not in every case been care- 
ful to make adequate provision. 

This is found in the extent to which the records of the different instru- 
ments are commonly kept independently of each other ; so that the rela- 
tions which connect fluctuations of atmospheric conditions of different 
kinds, or the degree to which these are mutually influential, are kept out 
of view, or are at least not made purposely and prominently conspicuous. 

We occasionally even see curves which have been elaborately pro- 
jected from observations of the thermometer, the barometer, the psychro- 
roeter, and the anemometer, made at our principal observatories, pre- 
sented on sheets entirely separate, as if the phenomena recorded by each 
of these iustruments were without natural connection with the rest, aud 
were possessed of an interest quite special and peculiar ; but it is obvious 
that if we ever arrive at any better knowledge of the laws regulating the 
weather than we have yet attained, it will only be by studying tbe 
weather as a whole, and carefully considering what changes in each 
class of atmospheric conditions have a necessary connection with other 
changes simultaneously going on in every other class. 



AUTOMATIC METEOROLOGICAL REGISTERS. 571 

The system, therefore, of meteorological record which we need, is one 
in which every class of fluctuating atmospheric conditions shall be 
graphically recorded, and in which the curves of record shall be in 
immediate juxtaposition upon the same sheet. We shall then have a 
complete picture of the weather delineated by the hand of nature her- 
self; and the study of the mutual relations of its different phenomena 
will be reduced to the last degree of simplicity possible in a problem of 
so difficult complication. 

The importance of this consideration appears to have been appreciated 
by some of the exhibitors whose instruments for automatic meteorologi- 
cal registration have been referred to above ; but in none of these 
forms of apparatus has the object here indicated as so desirable been 
realized in a manner so entirely satisfactory, as in the meteorogrcuphe 
exhibited by Father Angelo Secchi in the section of the Pontifical 
States. 

Several of the registers exhibited were confined in fact to the object 
of recording the indications of a single instrument exclusively. Thus, 
wind-registers were presented by Mr. Beck, of London, Mr. Herve- 
Mangon, of Paris, and Mr. Parnisetti, of Italy ; temperature registers 
by Mr. L. Jean, of Vienna, and Mr. A. G. Theorel, of Upsal, Sweden ; 
pressure-registers by Mr. Breguet, of Paris, &c ; while of the exhib- 
itors who aimed to extend their provisions to a larger number of the 
atmospheric phenomena, only a few had so arranged their constructions 
as to permit the several records to be inscribed on the same sheet. Thus, 
Mr. Hipp, of Neuchatel, Switzerland, exhibited a barogrcvplie and a 
thermograjpJie ; Mr. Gros-Claude, of Geneva, registers for the barometer, 
thermometer, and hygrometer j Messrs. Hasler & Escher, of Berne, regis- 
ters for the barometer, thermometer, pluviometer, and anemometer, &c. 
These last very ingenious instruments were constructed under the direc- 
tion of Professor Wild, director of the observatory of Berne and professor 
of physics in the university of that city. A single regulating clock 
determines the advance of all the register sheets at a common rate ; so 
that these may be assembled side by side for purposes of comparison. 
A registering apparatus by Mr. J. Salleron in the French section records, 
in parallel divisions of the same sheet, the direction and velocity of the 
wind, the height of the barometer, and the fall of rain. In all the instru- 
ments above named, the mark is made by the action of electro-magnets, 
of which the circuit is periodically closed by clock-work. Most of them 
require a new sheet of record to be introduced daily ; but the apparatus 
of Professor Wild is adapted to receive, in the form of a roll, a sufficient 
amount of paper to last for many days or even weeks ; and during this 
time it requires no attention except to wind up the clock at the end of 
every eight days, and to see that the battery remains in good condition. 

By far the most interesting and the most important of the self-regis- 
tering meteorological instruments exhibited is the meteorograplie above 
mentioned, by Father Secchi. This instrument, apart from its scientific 



572 PARIS UNIVERSAL EXPOSITION. 

interest, has excited much admiration for its elegant proportions, its 
superior workmanship, and the beauty of its finish. Its height is seven 
or eight feet, upon a base about six feet by two. The lower portion is 
inclosed in polished mahogany 5 the upper is glazed, and contains the 
apparatus of registration. Surmounting the whole is an elegant clock, 
which regulates the motion of the tablets on which the registration is 
made. Of these there are two, one occupying each of the broad faces of 
the instrument. The clock also regulates the movements of many sub- 
ordinate parts of the apparatus. 

The object of employing two tablets is not to register a portion of the 
recorded phenomena on one and the rest on the other, which woidd be a 
violation of a principle regarded by Father Secchi as of the highest im- 
portance, viz: the presentation of a complete system of records side by 
side ; but it is to obtain records on different scales, of which the larger will 
permit a better examination of the details of the variations, especially 
when these are sudden and violent, while the less brings them into more 
compact form and facilitates comparison. The sheets are of a size suited 
to a large portfolio; and as they are removed from the instrument, they 
are preserved in their order and are periodically bound. As the meteor *o- 
graplie has been for eight years in operation in the Collegio Romano, at 
Rome, its records form now quite a series of volumes, some of which, by 
the courtesy of Father Secchi, the reporter has been permitted to exam- 
ine. No one from an inspection of these records could fail to be strongly 
impressed with the evidence they present of the importance, in the study 
of meteorological questions, of having all the elements of the problems 
involved placed side by side. 

The tablet on the principal face of the instrument gradually descends, 
under the action of the clock, and completes its course in two days and 
a half. The one on the opposite side occupies ten days. The sheets of 
paper on which the record is received are faint-lined in red both vertically 
and horizontally; the divisions on the vertical sides indicating time, 
and those on the upper and lower borders the instrumental readings. 

The first face, devoted to records on the larger scale, gives the indica- 
tions of the barometer and of the wet and dry thermometer, but omits 
the winds, which are sufficiently represented in the resume of all the 
phenomena on the other side. The barometer is the balance barometer 
invented by Father Secchi himself in 1857, though, as be states, he has 
since discovered that something of the same kind had been suggested 
about two hundred years ago by 3Ioreland, though apparently never 
used. The tube is of forged iron, bored very truly cylindrical to a diam- 
eter of two centimeters; but the superior part has a bore of six centi- 
meters, in consequence of which the fluctuations of the mercurial column 
occasion greater differences of weight than would occur in a uniform 
bore, and thus render the instrument more sensitive. The lower extrem- 
ity of the tube is embraced by a cylinder of wood, which, plunging into 
the reservoir of mercury, sustains the principal part of the weight of the 



SECCHI'S METEOROGRAPH. 573 

instrument, and reduces very much the pressure on the pivot of the bal- 
ance. The oscillations of the balance are communicated, by an inge- 
nious system of levers, to two pencils, by which they are recorded on 
both tablets at the same time, on a scale of enlargement of one to four 
and a half. 

Two mercurial thermometers, of which the tubes are open at the top, 
furnish the indications for temperature and humidity. At the bottom 
of each of these tubes a small platinum wire fused into the glass makes 
metallic communication with the mercury in the interior. The bulb of 
one of them is dry; that of the other is covered with muslin kept con- 
stantly wet. Into the open tubes of the thermometers are introduced 
the extremities of two wires of platinum connected with a slider which 
periodically descends, causing the wires to make contact with the mer- 
cury in the tubes. The desceut of this slider is produced by a lever sys- 
tem connecting it with a little car running on a railway before the tablet 
of record. At the end of every fifteen minutes the clock puts in motion 
a mechanism which causes this car to run along the railway operating 
the levers which cause the slider to descend. The car carries also a pen- 
cil directed toward the tablet. As the slider descends, it will be the 
dry bulb thermometer in which the entering wire will first make electric 
contact. At the instant this occurs the pencil falls on the tablet and, 
in the further advance of the car, it traces a line which continues unbroken 
until the moment when contact is made in the wet bulb thermometer. 
The circuit closed by this contact operates a magnet which breaks the 
circuit of the first, and the pencil is immediately retracted. The car 
after having completed its course immediately returns, and the pencil 
marks, a second time, in returning, the trace it had made before. 

The hour of rain, and the duration of the rain, are marked upon this 
face of the instrument by means of another pencil controlled also by an 
electro-magnet. The circuit of the magnet is opened and closed by a 
little water-wheel placed under a water conductor in any convenient sit- 
uation within or without the building. The quantity of water falling 
cannot be thus registered. This determination has to be made by a 
special contrivance. At one side of the instrument near the top is a 
disk of eight or ten inches in diameter, turning on an axis which carries 
also a pulley, over which passes a chain. One end of this chain carries 
a weight, the other is attached to a vertical stem proceeding from a float 
in a reservoir in the base of the instrument. The water from the rain 
gauge is conducted to this reservoir, causing the float to rise; and this 
necessarily causes the disk to turn. To the solid disk is attached a cor- 
responding disk of paper, and upon this paper rests the point of a pen- 
cil, which has a gradual motion outward from the center at the rate of 
about five millimeters a day. If in the meantime there is no rain, the 
disk will not turn, and the mark of the pencil will be a radial line. But 
should rain occur, the trace will become a circular arc, or strictly speak- 
ing, a spiral; and the amount of angular rotation will be a measure of 



574 PARIS UNIVERSAL EXPOSITION. 

the quantity of rain fallen; which, however, is also indicated on a verti- 
cal scale by an index carried by the vertical stem of the float. 

On the other face of the instrument are recorded the indications of 
the barometer, as just mentioned, and also those of the hours of rain and 
those of the thermometer; but this time it is not the mercurial ther- 
mometer of which the indications are registered, but a very simple 
metallic thermometer formed of a stretched copper wire. This wire is 
stretched in some place where the temperature represents the tempera- 
ture prevailing in the shade at the time, and the variations of its length 
are transferred to the tablet by mechanical means entirely, the magni- 
tude of the movement being enlarged in any desired proportion. Father 
Secchi states that this thermometer will give indications to one-quarter 
of a degree centigrade. 

There remain to be described the modes of registration of the direction 
and the velocity of the wind. The directions of the wind are recorded 
by four pencils resting on the tablet, and attached to as many levers 
having a limited lateral oscillation as they are acted upon from time to 
time by electro-magnets in communication with the wind- vane and the 
anemometer. There is a pencil for each of the cardinal points of the 
compass, and each has its separate electro-magnet. All these magnets 
have their bobbins in an electric circuit passing through the wind- vane 
and the anemometer, which is therefore so far common to them all. The 
anemometer, which is the cup-anemometer known as Kobinson's, closes 
the circuit once in each revolution. On the other side each magnet has 
a separate circuit which communicates with a metallic quadrantal arc 
corresponding to the point of compass to which it belongs ; all the four 
quadrants being assembled to form a circle surrounding the rod of the 
wind- vane, but being insulated from each other. The wind- vane carries 
a tongue of elastic metal which traverses the circle just spoken of, and 
which, at every turn of the anemometer, closes the circuit for one at least 
of the magnets, and accordingly puts one at least of the pencils above 
spoken of in motion. If the tongue happens to rest on two quadrants 
at a time, at their junction, or if by oscillation it passes rapidly from 
one to the other, two pencils may be operated at once. This will indi- 
cate a wind intermediate between the cardinal points corresponding 
to these two pencils. It will be seen that the distinction of the directions 
of the wiuds is not very nice. Father Secchi remarks, "Experience 
proves that, in practice, this system satisfies the wants of meteorological 
science in its actually existing state." This is the only remark of his 
on the subject which is likely to be accepted with hesitation. 

The apparatus for registering the velocity of the wind is somewhat 
complicated. At the top of the instrument, on the side opposite to the 
principal dial of the clock, are placed a number of counting dials, by 
means of which an actual register can be made in kilometers of the 
whole space the wind may be presumed to have passed over during a 
determinate period. The first of these counters is set forward one tooth 



SECCHl's METEOROGRAPH. 575 

at every revolution of the anemometer, by means of an electro-magnet . 
This is all that it concerns us to consider, in describing the mode of 
registration on the tablet. Upon the axis of this first counter there is a 
pulley on which is wound up gradually a little chain. This chain, through 
a system of levers, draws in a horizontal direction a pencil resting on 
the tablet. As the counter turns slowly, the pencil advances very grad- 
ually along the paper; but the rapidity of its progress, and the extent 
of its progress in a given time, are necessarily dependent on the velocity 
of the wind. At the end of each hour the pulley is suddenly set free on 
the axis of the counter, and as the pencil is always acted on by an opposite 
weight resisting its advance, it immediately runs back to the starting 
point; after which the pulley becomes locked again, and the operation 
is renewed. The length of the line traced in each hour becomes thus a 
visible measure of the mean velocity of the wind during the same time. 
This very brief and imperfect account of one of the most ingenious 
combinations of mechanism to effect a purpose of great practical utility 
and of extreme interest to science which the Exposition embraces, or 
which has been produced in recent years, may serve to convey some idea 
of the advantage which would be likely to accrue to the progress of 
meteorology could so efficient a mode of representing its phenomena be 
introduced into observatories generally. There is nothing but theexpens- 
iveness of the apparatus to prevent; but that, unfortunately, is consid- 
erable. For an instrument of the same finish and elegance as the one 
exhibited in the Exposition, the constructor, Mr. Brassart, of Borne, 
states the price at eighteen thousand francs. For a more modest model, 
such as is actually used in the observatory of the Collegio Roinano, con- 
taining all the registration apparatus complete, it is ten thousand francs. 
But for a simplified meteorograjrfie provided with only the ten-day tablet, 
and with cabinet work entirely plain, it is as low as three thousand. These 
prices will prevent the introduction of the instrument into any but well- 
endowed institutions, and will be likely to operate its exclusion from 
the minor observatories altogether. 



CHAPTER XVII. 

GEODESY AND NAVIGATION. 

Method of measurement in surveying— Telemetric methods — Rochon's double 
refraction telescope — lorieux's binocular telemetric glasses— the stadi- 
meter— porro's stenallatic telescope — divided object-glass telescope — 
Divided eye-glass telescope — Telemetric double telescopes — Balbreck's 
double telescope reflecting telemeter— electric telemeters— prism tele- 
METER — Telemetric single telescopes— Theodolites— Dabbadie's traveling 
theodolite— Leveling instruments— Pistor and Marten's sextants— Lau- 
rent's — Davidson's — Nautical compasses — Wedel-Jarlsberg's — Ritchie's — 
Deep-sea sounding— Trowbridge's deep-sea apparatus— Morse's bathometer. 

I.— TELEMETEICAL APPABATUS. 

The simplest mode which suggests itself for determining the distance 
between two points of the earth's surface is to apply a measure of known 
length along the line connecting them. This is the method used in com- 
mon surveying. It admits of a near approach to accuracy when the 
inequalities of the intervening ground are inconsiderable and the meas- 
uring instruments accurate. But great care and skill are necessary, 
even under these circumstances, in order to preserve the line direct 
and to insure the commencement of each successive measurement from 
the exact point at which the last one ended. Over broken ground, 
water-courses, lakes, and mountainous districts, direct measurement is 
always attended with great difficulties, and is often impracticable. For 
geodetic operations of importance it is therefore usual to call in the aid 
of trigonometry. Direct measurement is indeed still necessary, even in 
this case, in order to establish a base for the commencement of opera- 
tions ; but the ground on which this base is measured may be chosen at 
pleasure, and need not even be in the vicinity of the line or the surface 
of which the dimensions are required. After the base has ouce been 
measured — a process which in large works of geodesy is a very small 
part of the whole, and one which may therefore be executed with all 
necessary care and deliberation — the remaining field-work is reduced to 
the observation of angles; in the performance of which, instrumental 
accuracy has been carried to an extraordinary degree of refinement. 

There are many purposes, however, for which it is desirable to ascer- 
tain the distances between points visible from each other, with something 
less than absolute accuracy, yet more accurately and more expeditiously 
than they can be directly measured. To accomplish this object a variety 
of instruments have been devised, some of them displaying remarkable 



TELEMETRICAL APPARATUS. 577 

ingenuity. In tbe collection of astronomical and geodetical instruments 
exposed by Messrs. Brunner Brothers, of Paris, were embraced several 
of these. 

When an object at a distant station and visible to the observer is of 
known dimensions, the problem presents comparatively little difficulty. 
Any instrument by which angles may be accurately measured will suffice 
to resolve it. If the two stations are on the same level, it will only be 
necessary to measure the angle at the observer's eye subtended by the 
object ; and this being ascertained, a triangle will be given in which all 
the angles and the base are known. If the stations are not on the same 
level it will be necessary additionally to measure the angle of elevation 
or depression of the object observed. The distance sought, however, 
can only be found by this process by means of a solution of the triangle 
obtained as above, and this involves a somewhat troublesome numerical 
operation. The necessity of such a calculation may be avoided by the 
preparation of tables in advance in which angles may form the arguments 
or entering numbers at the side, while the various possible linear dimen- 
sions of objects observed may furnish the arguments at the top. The 
distance corresponding to any given object and angle may then be found 
by inspection. It is convenient, nevertheless, to be relieved of even the 
necessity of consulting tables, and this may be done by graduating the 
instrument itself in such a way that, after any observation, the index 
shall point to a number telling how many times the distance is greater 
than the object. Suppose, for instance, that with such an instrument an 
object ten feet in height or in breadth is observed, and that the index 
marks the number 528. The distance of the object will then be 528 times 
ten feet, or 5,280 ; that is, one mile. 

rochon's double-image telescope. 

Bochon's double image telescope is an instrument of this kind; that 
is to say, its indications multiplied by the known diameter of the object 
give the distance ; but it is not what we have been supposing above, an 
angle-measuring instrument. The two images which this telescope gives 
of the same object are produced by a doubly-refracting prism of Iceland 
spar within the barrel of the instrument, which divides the converging 
pencil of rays into two pencils deviating from each other by a determinate 
angle. Two images are therefore formed by these pencils after their 
deviation $ and it is evident that their separation from each other will 
be greater the farther they are formed from the prism. When the dis- 
tance of the object is given, the distance of the image from the object- 
glass is of course fixed ; but the prism is movable, and by means of a 
rack and pinion it may be transferred from one end of the tube to the 
other. On observing the object through the telescope, if the images 
overlap, the prism must be moved farther toward the object-glass. If, 
on the other hand, they are separated by an interval, it must be drawn 
37 1 A 



578 PARIS UNIVERSAL EXPOSITION. 

toward the eye-glass. When the two images are in exact contact, the 
index on the slide which carries the prism points on the exterior of the 
barrel of the telescope to the number denoting the distance. It is evi- 
dent that, inasmuch as the size of the image is less as the distance is 
greater, the numbers marked on the barrel must increase from the 
object-glass in the direction of the eye-glass. Such an instrument may 
be graduated by the indications of theory, but it is safer to determine 
the scale by trial. 

BINOCULAR TELE3IETRIC MARINE GLASSES. 

Mr. Lorieux, of Paris, exhibited a binocular marine glass, designed to 
determine distance by the measure of the angle subtended by a known 
object $ and this means by a construction which permits the axes of the 
two tubes to be thrown out of parallelism by an angular movement 
around an axis joining the two eye-pieces. The effect of this move- 
ment is to double the image of an object which appears single when 
both axes are in the same plane. One of these images will appear 
directly over the other, and when they are in contact by their edges, the 
angular movement of one tube which has been required to produce this 
effect will be, of course, equal to the angle subtended by the object at the 
eye of the observer. Before making an observation the instrument should 
be adjusted to show but a single image of some sharply-defined object, 
and any error of adjustment of the index on the scale should be cor- 
rected. Another instrument, also binocular, exhibited by the same 
optician, was designed to determine distances by a simpler means. It 
has been a plan frequently adopted in instruments of this class to intro- 
duce a micrometer, with movable lines, into the focus of the object- 
glass of a telescope, observing by means of a Eamsden eye-piece. The 
size of the image decreasing as the distance increases, the measure of 
its diameter becomes indirectly a measure of distance. The eye-pieces 
of marine glasses being negative, there is no real image formed within 
the tube, and hence a micrometer cannot be employed with such a glass. 
But by interposing in front of the object-glass an opaque body, as a 
plate of metal, the field of view can be reduced ; and thus, in effect, the 
varying breadth of the field may be made to subserve the purposes of a 
micrometer. If a. vertical plate be interposed on each side of the axis 
and the two be made to approach and recede symmetrically, by means 
of a screw, right-handed on one side and left-handed on the other, they 
may be brought to include between them any object of known dimen- 
sions; and as, when the object is near, the opening must be wider to 
allow of this than when it is more distant, the instrument becomes a 
telemeter, or distance measurer. For facility in use it is more convenient 
in general that the edges of the plates should be horizontal than ver- 
tical; but either construction may be employed. The principle here 
explained is that which has been adopted in the second of the instru- 
ments of Mr. Lorieux mentioned above. 



TELEMETRICAL APPARATUS. 579 

THE STADIMETER. 

In Mr. Brunner's collection was exhibited an instrument called the 
stadirneter, invented by Messrs. Peaucellier and Wagner, of the imperial 
topographical corps of France. This is a horizontal rale bearing strongly- 
marked divisions, which are numbered from the centre in both directions, 
the whole being supported by a vertical rod in the manner of a signal 
mark on an engineer's levelling rod. The marks are in white on black, 
for the sake of greater distinctness, and the numbers are inverted that 
they may appear upright in an inverting telescope. This part of the 

Fig. 120. 




X> 



HiiBninBMHtHBj 



Brunner's Stadirneter. 

apparatus is represented in Fig. 120. In the focus of the eye-piece are 
two fixed micrometric lines, and the determination of distance is made 
by observing how many divisions of the stadirneter are embraced between 
these lines. 

The manner of observing is as follows : The stadirneter is fixed at the 
distant station, with its support truly vertical, and the plane of its arms 
at right angles to the line to be measured. The observer at the tele- 
scope turns the instrument in azimuth by means of a tangent screw, so 
as to make the two lines of the micrometer cat, if possible, two simi- 
larly numbered divisions. Thus if these lines fall exactly on the 
divisions 1, right and left, the distance is one decameter; if on the 
divisions 2, it will be two decameters ; if on the divisions 3, three deca- 
meters, and so on. 

But, as a general rule, the divisions will not fall exactly on the wires. 
In this case after observing the largest division which the lines of the 
micrometer will embrace, the division of that number on the right-hand 
arm x 1 is brought into exact coincidence with its wire, and by turning 
an index, fc, in a dial marked J, the arm x is moved outward horizontally 
until coincidence is obtained with the corresponding division of that 
arm also. A horizontal index marked h shows bow many subdivisions 
the arm is thus moved. Each space between the divisions is subdivided ? 
as will be seen, into five parts. And as the value 1-1 is equivalent to a 
decameter, each of these spaces is equivalent to a meter. As the distance 
moved may not be an exact number of these subdivisions the fractions 
below a meter will be given by the dial J. The index of this dial makes 
an entire revolution in advancing the arm x one subdivision. The dial 
itself is divided into ten parts. Each of these parts corresponds to 
a decimeter. The centimeters may be estimated from observing the 
final position of the index Jc between the divisions of the dial. 



580 PARIS UNIVERSAL EXPOSITION. 

The two arms are constructed in parts which fold back on each 
other, hinging half-way between the numbers eight and nine. For 
moderate distances, not exceeding eight decameters, the outer wings need 
not be unfolded. When they are employed, the distance measured may 
be increased to fourteen and a half decameters. There is also in the 
telescope a central line, dividing the space between the micrometric 
wires into two equal parts. For distances exceeding one hundred and 
forty-five meters this central line may be used with one of the lateral 
lines, in which case the divisions of the stadimeter indicate double 
decameters. 

The telescope has another peculiarity, which is of great advantage in 
measurements in which the two stations are not on the same level. The 
indications which it gives are the true distances as projected on a hori- 
zontal plane. This result is accomplished by means of a construction 
called by its originator, Mr. Porro, stenallatic. 

Since the number of divisions on the stadimeter intercepted by the 
fixed lines of the micrometer is the measure of the distance, this peculi- 
arity of the construction must consist in maintaining the dimensions of 
the image at the same value, wherever the object may be situated in the 
same vertical. But inasmuch as the distance of the object from the 
observer increases as it is elevated in a vertical line above, or depressed 
in the same manner below the horizontal, in the ratio of the hypothe- 
nuse of a right-angled triangle to the base of the same triangle, or in 
that of the radius to the cosine of the angle of elevation or depression, 
the image in an ordinary telescope grows smaller under these changing 
conditions. The stenallatic contrivance is designed to counteract this 
effect. It does so by means of the following expedient. 

In telescopes and in microscopes, when it is desired to exalt the mag- 
nifying power without increasing materially the length of the instru- 
ment, it is a plan which opticians frequently adopt to introduce within 
the tube a concave lens, called an amplifier. The effect of this upon 
the magnitude of the image varies with the position which it occupies 
between the objective and the ocular. As in the stenallatic telescope, 
the object to be gained is a virtual enlargement gradually increasing 
and always exactly compensating the diminution of size produced by 
the increasing distance of the object, it is easily seen that this effect 
may be secured, provided we can contrive a mechanism which shall 
move an amplifying glass in the interior of the telescope, in such a man- 
ner that its optical effect shall be just equal and opposite to that pro- 
duced by varying the position of the observed object in the vertical 
passing through it. 

In order to devise such a contrivance, it is necessary to know the 
relation which subsists between the image and the object observed, as 
to their linear dimensions. To ascertain this, we consider — 

1. That when an image is formed by a single lens, the diameters of the 
image and object are to each other directly as their distances from the lens. 



TELEMETRICAL APPARATUS. 



581 



2. When an image is formed by the joint or consecutive action of two 
lenses, we may treat the case as if the first of these two lenses had pro- 
duced its effect without the presence of the other ; and then regard the 
image thus formed as the object of the second lens. 

3. If a is the distance of an object from the center of a convex lens, 
b the distance of the, image formed in the focus conjugate to «, and / 
the distance of the principal focus, or focus of parallel rays, the law 
will be found to hold, which is expressed in the equation 



1_1 1 
f~a+b 



Whence, b. 



rf 



a—f 



And if A be the space on the stadimeter, whose image is included 
between the lines of the micrometer, and B the actual distance between 
those lines themselves, then (according to [1] above,) 

a—f f ( a —f) x 

As / is a constant, we may conveniently put x for a — /; and this 
letter will then represent the distance of the stadimeter from the focal 
point of the object glass exterior to the glass. 



B 6 











Ti 








c 


L 

r 


















~~---|0 


F ^\ 





^^ Y > 




" A. 



Fig. 121. 

In this figure, L represents this object glass ; A, the place of the stad- 
imeter ; B, the place where (in the absence of the other lens represented) 
the image of A would fall ; aud F and F 7 the positions of the focal points 
of L, interior and exterior. 

4. In proceeding to find the place and magnitude of the ultimate image 
formed by the joint action of the two lenses L and L/, the object, or 
radiant, in reference to 1/ must be assumed to be at B. It is a neces- 
sary condition, in the case in hand,' that B should be nearer to L' than 
F', its principal focus : otherwise the rays after being acted on by 1/ 
will form no real image, while it is essential to the purpose in view that 
there should be a real image in the plane of the micrometer spider-lines. 
This being understood, we shall have the radiant, (negative in this case,) 
the principal focus, and the ultimate image, in the order which the figure 
shows, at B, F' and C. Represent their distances from the centre of 17 
by the letters &', /' and &. We shall have then 

111 h'f 

_ = t — i. Wh pti pp. o'= °-> . 

f V 



& f-b' 

And if C and B be taken as the measures of the images formed at 
the points marked by those letters respectively, we shall have, 
Q_c'_b'f ,,_ f 
B V f-b' ' f'-b 1 ' 



582 



PARIS UNIVERSAL EXPOSITION. 



Iii this expression, if we put for B its value found above, (3) there 
will result, 



Ca_ /' . 

a/ r-v ' 



whence 



A._{f'-V) a? 



C ff' 

Now if s is the space or distance between the lenses, V is equal to b—s. 
And in (3) above, we have 

b-. 



,af -^/__ >+/)/ _ f+ f. 
a—f x x x' 



So that b'=b- 
going,gives 






?, which, substituted in the expression fore- 



A 



(f , -f- f Us)x 

X 



(s+f'-f)x-f\ 



ff ff 

In the figure, s is OO',/' is O'F', and / is OF. Whence s+f -/is 
FF' the distance between the principal foci of the two lenses. Put then 
this distance =d, and we shall have 

A_dx-f 2 

C ff ' 

Since /and/ 7 are constant quantities, if the product, dx, can be made 

constant also, the ratio of A to C will be unaltered, or the image will 

remain of the same constant magnitude. We can vary this distance 



d, by moving the amplifying lens. 



What is necessary, is, that we shall 

( move it so that 

d shall vary in- 

" verselyasj?. If, 

c in this figure, 

Fi S' 122 - BAbethehori- 

horizontal distance of the object, then the distance BC or BC, under the 

angle of elevation or depression, ABC, ABC, will be expressed by 

BA ™„ BA 




BC 



r . BC 



cosABC cosABC 

Hence the distance between the foci of the two lenses must be made to 
vary directly as the cosine of the angle of inclination to the horizon. 

A mechanism producing 

a variation according to 

this law is illustrated in 

principle in Fig. 123. Let 

A B be two fixed points in 

a horizontal bar, supported 

by an upright P. Attached 

Fig - 123, to these two points let 

there be two arms so pivoted as to turn freely. The arm pivoted at B is 

to be constructed hollow ; and a rod sliding within it is to be pivoted to 




TELEMETRICAL APPARATUS. 



583 



the extremity D of the arm pivoted at A. In consequence of the con- 
nection thus established, neither of the two arms can turn without 
causing the other to turn ; and with every change of position of the 
arms there will be a variation of the distance between the points B and 
D. This distance will reach its maximum when the arm takes the hor- 
izontal position AO. Suppose now the arm AD to be equal to the dis- 
tance AB. The triangle ABD is isosceles, and the base BD has the 
value expressed in the equation, 

BD=2ABcosABD. . 

Now since AB is horizontal, the angle ABD is the angle of inclination 
of BD to the horizon; so that if the two lenses, in the case supposed, 
were fixed so that their focal points should be at the points B and D, the 
distance of these points from each other would vary according to the 
required law. 

The manner of adapting a contrivance of this description to a tele- 
scope, so as to make the instrument fulfill the prescribed condition, is 
shown in Fig. 124. Here 
we have the triangle 
ABD of the previous 
figure repeated in the 
triangle AOD; and on 
the other side of the 
middle point G, of the 
horizontal bar AB, we 
have another similar 
triangle, BOE. AD, 
AO, BO, and BE, are 
all equal to each other. 




Fig. 124. 



The tubeDE, which is pivoted at 0, has within 
it two sliding tubes, one of which carries the object-glass, and the other 
the eye-glass. These sliding tubes are moved by the arms AD, BE, which 
are connected with them at the points D and E, by pivots passing 
through slots in the outer tube. It is evident in this construction, as in 
the former, that 

DE=2ABcosACD. 

Suppose, therefore, that the points DE are such that, when the tel- 
escope is horizontal, the distance between them is equal to the distance 
between the principal foci of the glasses, taken on either side of the 
glasses respectively, but both on the same side, it will be true of 
them in any other position that their distance will be such as to give 
always the true horizontal distance of the object observed. 

The principle of the necessary mechanism being thus established, it 
becomes a mere matter of mechanical detail to perfect the application. 
It is unnecessary, therefore, to descend more minutely into the descrip- 
tion of the instruments exhibited, in which it was exemplified. One 
observation, however, may be added. Inasmuch as it appears from the 



584 PARIS UNIVERSAL EXPOSITION. 

examination of the theory of stenallatism above given, that the horizon- 
tal distance indicated by the instrument is measured from a point in front 
of the object-glass, and as far in front of it as the distance of its prin- 
cipal focus, it is evident that when the telescope is inclined, this point 
describing a circular arc will occasion a slight error in the indication. 
In general, the error will be too small to require correction, except for 
purposes which demand severe exactness. The corrections may be easily 
tabulated and applied when necessary. Mr. Porro has not been willing, 
however, to permit even this imperfection to impair the theoretic perfection 
of his instrument. He has introduced an additional mechanical con- 
trivance, by means of which the whole body of the telescope is advanced 
or retracted in the direction of its length by the exact amount necessary 
to preserve the constancy of position of the initial point of horizontal 
measurement, thus making the instrument independent of tabular cor- 
rections. In this improved form, he gives to the instrument the name 
of the anallatic telescope. 

Several forms of double-image instruments have been constructed and 
to some extent heretofore employed, which were not present in the 
Exposition, or if present were not observed. In one of these the object- 
glass is divided through the middle, like that of a heliometer, showing a 
single image when the two halves of the lens are in their original position 
so as to form one whole, and two when the two halves are displaced by a 
movement in the direction of the line of division. The amount of 
movement necessary to bring the two images of a known object into 
contact by their edges, serves to indicate the distance; which is then 
inscribed on the scale in a number of which the measured dimension of 
the object observed is the unit. A simple and exceedingly portable 
instrument analogous to this is one in which the eye-glass is divided. 
The telescope is on the Galilean plan, and the movement of the divided 
eye-piece is effected by means of a lever which can be managed by the 
thumb of the hand which holds the instrument. This is designed to be 
used on horseback, the whole being small enough to be carried in the 
side pocket of the coat. For cavalry officers it is very convenient, giv- 
ing approximately the distance of a man or body of men. by assuming 
six feet- as the average height of a soldier with his chapean. The scale 
is so inscribed that its indications may be read while the instrument is 
held in a manner convenient for observation. 

TELEItfETKIC DOUBLE TELESCOPES. 

For the determination of distances by means of observations upon 
objects whose dimensions are unknown, it is necessary in general ro 
obtain a parallax, or angle subtended at the distant station by a base at 
the point of observation. Instruments have been constructed with two 
telescopes fixed at the extremities of a bar or rod of determinate length. 
one of them being movable in azimuth over a divided circle, while the 
other is fixed. When the index of the movable telescope is at the zero of 



TELEMETRIC DOUBLE TELESCOPES. 



585 



the graduation, the two axes ought to be parallel. An adjustment to 
this condition is effected by observing a horizontal object, placed at a 
convenient distance for the purpose, equal in length to the bar to which 

Fig. 125. 

11 L' 





Balbreck's Telemetric Double Telescope. 

the telescopes are attached. When one extremity of this object is 
brought exactly to the central line of the micrometer of the telescope at 
the corresponding end of the bar, the other must be turned in azimuth 
until a similar coincidence is obtained with the other end. The axes of 
the telescopes are then parallel, and the circle or the index must be 
moved, without disturbing the telescope above it, until the index marks 
truly zero. If then both telescopes are directed at the same distant point, 
the parallax may be directly read. 

Mr. Balbreck, of Paris, exhibited an instrument of simpler construe-' 
tion, founded upon the same principle, which is represented in plan in the 
figure. A square box contains two mirrors M and M 7 , turning on verti- 
cal pivots at their middle points. Their movements are commanded by 
tangent screws, represented at m and m', each carrying a divided circle 
with an index by which the amount of movement may be read. These 
mirrors are in part silvered and in part transparent. They are represented 
in Figs. 126 and 127. The parts marked r are silvered on one side, and 
those more darkly shaded on the other. The 
parts unshaded are transparent. The box is 
mounted on a tripod by means of a central pivot, 
around which it may revolve horizontally. This 
pivot is fixed to the tripod by a ball and socket 
joint, which allows the plane of revolution, if Fig. 126. 

necessary, to be inclined. Two telescopes are 
also attached to the apparatus, each making a 
right angle in the interior of the box; a rectangu- 
lar glass prism being placed in the angle to change 
the direction of the rays by total reflection. The 
eye-pieces of these telescopes are presented at 
right angles to the axis of the box in opposite directions. The distance 
between the centers of the mirrors is one meter. In the sides of the box 
opposite the mirrors are openings to admit the light from the object 
to be observed. 

The use of the instrument may be thus explained. Let us suppose, at 
first, that the two mirrors are at an angle of forty-five degrees to the 





586 



PARIS UNIVERSAL EXPOSITION. 



axis of the box ; and that the telescopes are parallel to each other, their 
axes being at right angles to that of the box. By turning the whole 
nstrurnent about its pivot, let the image of a distant point as seen by 
reflection in the mirror M be brought to coincidence with the central 
line of the micrometer in L. Then, through the transparent part of M* 
the same paint will be seen by reflection from the mirror M 7 , but not on 
the central line. The tangent screw m' must therefore be used to bring 
it to the center. Suppose O to be the place of the object. Then the 
rays O M and O M 7 will form an angle with each other equal very nearly 
to the parallax sought — that is, to the angle at O subtended by the base? 
one meter, which is the distance between the centers of M and M'. The 
mirror M 7 will, according to the well-known law of reflection, have been 
turned through an angle equal to half the parallax. Let now the box 
be revolved one hundred and eighty degrees on its pivot. The telescope 
1/ will now come into the position far observation, and the mirror M 7 
will be that which will reflect the right-hand image to the eye. This is 
the mirror which has been turned by the micrometer screw. When the 
image as reflected by it is brought to the central line by turning the box 
as before, the other image, now reflected from M, will be twice as far from 
the center as in the former case. By turning the tangent screw m, the 
mirror M will first come into parallelism with M 7 , when the appearance 
of things will be the same as that first presented, and afterwards passing 
beyond the position of parallelism, will bring the second image again to 
coincide with the first. The dial of m will then show twice as large an 
angular movement as that of m'; and this reading will be very nearly 
the true parallax. That it needs a correction to make it quite true will 
appear from examining the accompanying diagrams, Figs. 128 and 129. 

Fie-. 123. 




Second observation. 

Disregarding the angular form of the telescope, suppose the observer's 
eye to be at E, and that the object O is seen in the line G E. Another 



TELEMETRICAL APPARATUS. 587 

object 0', one meter distant from O, will be seen reflected from M ; intlie 
same direction, while another image of O will be observed in that mirror 
out of the center. When coincidence is established by turning M', the 
rays from O reflected from the second mirror will follow the line C C E. 
The mirror M' will then have a new position, which may be represented 
by M". 

Eevolving the instrument, the left-hand image will be seen in M", the 
reflected ray taking the direction 0' E, the axis of the box having now 
a position deviating from that which it had originally, by half the angle 
OCO'. M will have to be brought to the position W" in order to 
establish parallelism anew between the mirrors, when the object O' will 
be seen in the direction PC'E; and afterward to the position M"", to 
bring both images of O together. The angle M C W" is now very 
nearly the parallax, and for any but very exact determinations may be 
taken as the actual parallax. There is a slight error in the measure- 
ment, which arises from the fact that the line C P is not exactly equal 
to the line C 0. An exact correction is not simply effected ; but if the 
measured parallaxes corresponding to a series of known distances be 
tabulated, very accurate results may be reached. The instrument can 
be used very rapidly, and by repeating the observations in successive 
revolutions, the parallax may be doubled, trebled, &c, at pleasure. 

ELECTRIC TELEMETERS. 

Among the objects exhibited in the Austrian section by the war 
department of that empire there was an ingenious apparatus for meas- 
nsing the distances and determining the positions of objects in motion, 
by means of observations conducted simultaneously at two stations, dis- 
tant and not necessarily in view from each other. Electricity is here 
called in to assist in the determination. The inventor is Captain 
Kocziczka, of the imperial-royal corps of engineers. The following 
description is transcribed from a report to a scientific journal: 

" This apparatus requires two points of observation placed at a cer- 
tain measured distance from each other, and connected by a telegraph 
wire. At each of these stations a telescope is used for observing the 
object in view, and below the telescope a small table is placed in one of 
the stations, representing the map of the space in front of the observer. 
At one fixed point upon the table exactly below the axis of the telescope 
there is a long thin needle balanced upon a point, and connected to the 
telescope, so as to follow all movements of the latter and to be always 
parallel to its line of sight. Besides this, a second needle, which turns 
round a point which represents the second point of observation upon the 
small map, is placed upon the table, and this second needle is connected 
with the telescope of the other station by an electric arrangement. The 
movement of the distant telescope is made to cause this needle to turn 
to an equal angle with itself, in a somewhat similar manner to the mag- 
netic needles of the electric telegraph. The distance between the cen- 



588 PARIS UNIVERSAL EXPOSITION. 

ters of the two needles on the paper being made to scale, so as to repre- 
sent the measured distance of the two places of observation, it follows 
that the position of the two needles will indicate the two lines of sight 
of the two telescopes both fixed upon the same distant object, and the 
point where the two needles cross each other (one of the needles being 
slightly below the other) will correspond to the exact position of the 
distant object. If the latter is in motion, and the two observers follow 
its movements so as to keep it constantly in sight, the two needles will 
constantly change their position, and their point of intersection will make 
the same movements upon the map, on a small scale, as the distant 
object makes in reality ; the movements of the object and those of the 
point of intersection of the two needles being simultaneous. For pur- 
poses of warfare there are several applications of this instrument which 
will readily suggest themselves ; but similar instruments may be used 
with advantage for purposes of general surveys of land, and for similar 
operations where they are not unlikely to effect some considerable sav- 
ing of time, if properly employed." 

Another invention analogous to this was exhibited in the same collec- 
tion, originated by the Archduke Leopold, of which the object is to 
determine the moment when a hostile vessel passes over the position of 
a submerged torpedo, and also simultaneously to explode the mine. In 
this case two observers stationed at a distance from each other are 
necessary ; but the distance need not be measured. Supposing that a 
series of torpedoes is submerged in a straight line, oue of the stations is 
in the prolongation of that line, and the business of the observer is to 
watch the passage of the enemy's vessels across it. The other station 
commands a cross view of the same line ; and at this station the exact 
directions of the several submerged magazines are known. The tele- 
scope is of the ■ altitude and azimuth construction, and an insulated 
metallic arm which turns with the azimuth circle touches successively 
a series of insulated conductors, which communicate severally with the 
magazines toward which the telescope is at the moment directed. This 
contact closes a circuit which passes through both stations, and is broken 
at both, except when closed from time to time at the second in the move- 
ment of the telescope as just described, and intentionally at the first by 
the observer himself. It is the business of this first observer to touch 
the electric key whenever a vessel crosses the line. The second observer 
having his telescope directed at the same vessel, will necessarily, though 
unconsciously, close the circuit, if the vessel happens to pass over a mag- 
azine. The touching of the key at the first station thus completes the cir- 
cuit throughout, and the mine is exploded. But if the vessel happens 
to cross the line at a safe distance from any of these lurking dangers. 
there will be no contact at the second station, and the touching of the 
key will be without effect. 



TELEMETRICAL APPARATUS. 



589 



PRISM TELEMETER. 

The prism telemeter lias undergone a recent improvement, which 
renders it much more commodious in use than it was in its original form. 
The instrument consists of two prisms of observation, connected by a 
measuring tape or chain which serves to determine the length of the 
base on which the parallax is to be ascertained. These prisms are suit- 
ably mounted and provided with handles for the convenience of the 
observers. They are represented in their external appearance in Fig. 130 
annexed, and in section in Fig. 131. From the section it appears that the 




Prism Telemeter. 

prisms are four-sided, the reflecting sides, which are silvered, being at an 
angle of forty-five degrees to each other, so that a ray which enters at a, 
after two interior reflections emerges at d, at right angles to its original 
direction. The prisms are inclosed in the boxes marked C, (Fig. 130,) of 
which they occupy but 
half the height, so that the 
observer looking through e'. 



the tubes marked V, can 
see an object directly be- 
fore him through an aper- 
ture Y on the screen A, 
while he sees, at the same 
time,another object situa- Fi £- 131. 

ted to the right or left, by reflection in the prism, through the aperture F. 




590 PARIS UNIVERSAL EXPOSITION. 

The two objects thus seen are apparently coincident in direction ■ but 
really the rays coming from them to the prisms, cross in the interior of the 
prism (as seen at A, Fig. 131) at right angles to each other. The observ- 
ing apparatus is hinged to the screen at G, for convenience in packing. 
B, Fig. 130, is a box containing the measuring tape. 

This instrument was originally constructed in such a manner that in 
using it both observers stood facing the distant object. The observer 
on the left hand kept his position, while the observer on the right moved, 
at the extremity of the stretched measuring tape between them, until 
his prism was seen by the first observer, in coincidence with the distant 
object. The second observer then looking toward the distant object 0, 

Fig. 132, would.see coin- 
cident with it, not A, 
^____- — but some object or point 

b \ — — -"" behind A, as A 7 . If the 

Fi S- 132 - distance A A' (suppos- 

ing A' to be in the line A continued) could be accurately ascertained, 
the distance C A would become knowu, since, in the right-angled tri- 
angle A'BC, AB is the perpendicular to the hypothenuse drawn from 
the right angle, and 

AB 2 = AA'xAC; orAC = ^?!. 

In order to measure this distance, AA', the prism of the left hand 
observer was provided with a measuring arm or rod firmly attached to 
its handle, and extending, when the instrument was held before the 
eye, backward over the observers right shoulder. This arm carried, 
also, a sliding sight vane, which was to be the mark of the observer B. 
The position of this mark, first assumed conjecturally, was altered by 
the observer A, as required by the other observer, until the desired 
coincidence was secured. The reading on the arm then gave the dis- 
tance AA' sought, 

As it was customary, in practice, to employ a measuring tape of con- 
stant length, say twenty meters, the actual distances, AG, correspond- 
ing to the various readings with that length of base, were themselves 
inscribed on the arm, so that no calculation was required, except for 
interpolation in case the mark happened to fall between two gradua- 
tions. 

In the present construction, the two observers look directly at each 
other, and both see the distant object by reflection, the rays entering 
the instrument from the right for one, and from the left tor the other. 
In Fig. 131, if we suppose the distant object to be in the direction C A for 
the right-hand prism, then, if at the position B there is? a sensible par- 
allax, the object will appear in a somewhat different direction, as CB. 
And the observer must look at right angles to this direction, in order to 
see it, that is to say, in the direction E'B. By extending this line it 
will encounter some object, as A', which is to the right of A. The 



TELEMETRICAL APPARATUS. 



591 



recent improvement, which is dne to Captain Goulier, of the French 
engineer corps, consists in introducing between the prism B and the 
eye E 7 an optical compensator for the deviation, ABA 7 ,. which causes 
the emergent ray proceeding from A 7 to assume a direction at the eye, 
parallel to or coincident with AB. This compensator consists of a 
zone cut from the middle of a plano-convex lens of large diameter, and 
a similar zone cut from a plano-concave lens of the same size and radius 
of curvature. When two such zones are superposed concentrically 
upon one another, the spherical sides being in contact, they form unit- 
edly a plate of plane glass with parallel surfaces, incapable of changing 
the direction of rays of light transmitted through them. But if one of 
them is moved in the direction of its length, while the other remains 
stationary, then any ray which passes through the center of either will 
be bent by the other. 

In Fig. 133 we 
have first the 
concentric posi- 
tion of the plates, 
and the object O 
is seen in its true 
position by the 
eye at E. In Fig 
134 we have the 
convex lens dis 
placed toward D 
the right in A 7 
B 7 ; and the ray 
from O 7 will take 
the direction of 

P 7 after passing Fig. 133. Fig. 134. 

the system, and will escape the eye at E. But another ray coming 
obliquely from a different object, O, will be bent in such a manner as to 
fall into the direction O'E ; and if O AW be equal to the angle of parallax 
in any observation, say ABA 7 in Fig. 131, the system A'B'O'D', inter- 
posed between the eye and the prism B, will make the direction of the dis- 
tant object coincide with BA, or interposed between the eye and the space 
above the prism through which A 7 is seen in the same figure, it would 
make A appear in the direction E'B ; only that, in this case, it would 
be necessary to displace the convex band in the direction opposite to 
that shown in Fig. 134, or toward the left. 

This system of lenticular zones is introduced into the apparatus on 
the right, Fig. 130, at the point marked L. The concave band is fixed, 
and the eye always looks through its optical center. The convex band 
is movable, and is displaced by the observer by means of a milled head. 
The deviations of the ray produced by displacement are sensibly pro- 
portional to the displacements themselves, or to the distances of which 




o' 


0/ 

/ b' 




IV""— — -— — -^^ 


■n'h-- 


\ — — Ipt* 


jji 


-v ■ ■■■ u 



592 



PAEIS UNIVERSAL EXPOSITION. 



they are the parallaxes. These distances may, therefore, be marked on 
the scale which indicates the amount of displacement, when the length 
of the base line is fixed. 

Observations with this apparatus may be very rapidly made, and their 
facility is such that it is usual to take as many as ten successively, and 
to adopt the mean result. With a base of twenty meters, the mean 
error for distances up to one kilometer is one-half of one per cent. ; for 
distances as great as two kilometers or upward, two per cent., increas- 
ing as the square of the distance. By using a base twice as large — 
forty meters instead of twenty — the errors are reduced to one-half the 
foregoing. These determinations are made without a telescope. While 
a telescope may increase the accuracy of the results, it sensibly dimin- 
ishes the facility of observation. 



TELE3IETEICAL SINGLE TELESCOPES. 

A telemetrical telescope, invented by Captain Gautier, of the imperial 
artillery, was exposed by the constructor, Mr. Gravet Ta vernier, which, 
for its extreme portability and its remarkable accuracy, might be 
regarded as the most ingenious instrument of its kind in the Exposi- 
tion. It consists, as shown in the figure, of a tube about five inches in 
Fig. 135. length, having a 

short telescope with 
concave eye-piece, 
low magnifying pow- 
- er, and a narrow 
opening for vision at 
the end L, and two 
mirrors, M and M' ? 
making an angle of 






on— 



grr r^ 



i:s- 



J 



j£_ 



11= 



M- 



JK- 



E JNL'E- 

Gautier's Telemetrical Telescope. 

45° with each other, which occupy about half the breadth of the anterior 
part of the tube, leaving room for direct observation by means of rays 
coming in the direction I" O. In front still of the mirrors is a glass 
prism P, having an angle of about six degrees. This prism is attached 
to a ring which turns on the end of the tube, and is graduated with 
numbers increasing from to co. In the side of the tube, which, in the 
figure, is represented as seen from above, is an opening, O', through 
which rays coming from a distant object in the direction I ; may 
reach the eye at O, after undergoing two reflections from the mirrors 
M and M'. The mirror W is fixed to a lever EF, which turns on 
the pivot F, and is commanded by the screw E and milled head V 
and allows the angle made by the mirrors to be slightly varied. An 
index is attached to the lever EF on the under side, which indicates 
the exact angle at any time made by the mirrors. This angle may 
be read through an opening in the tube beneath the lever, which 
does not appear in the figure. The prism causes the rays entering 
the instrument from the objects toward which it is directed to deviate 



GAUTIERS TELEMETRICAL TELESCOPE. 



593 



by an amount, FKI", equal to half the angle of the prism, or three 
degrees. By turning the ring A, which carries the prism, the ray I'K 
will describe around I /7 K as an axis, a conical surface, so that its 
lateral deviation will vary between the extreme limits of three degrees 
right and left, passing through zero at the intermediate points of the 
revolution. 

In using the instrument it is first adjusted by turning the ring A until 
the mark go is under the index. The index of the lever EF must also 
be brought to its zero. In this condition the edge of the prism is ver- 
tical, and objects seen through the prism are displaced toward the right. 
The mirrors are also truly at 45° from each other, and the angle at N is 
a right angle. 

Let the observer be 
stationed at A, and let 
be the object of 
which it is required to 
ascertain the distance. 
Holding the instru- 
ment, which for conve- 
nience is attached by 
means of an India-rub- 
ber band to the end of 
the case in which it is D 
ordinarily carried in 
the pocket, before his Fig. 136. 

eye, the case serving as a handle, the observer brings the object into 
view; and then among the objects in the direction D selects a suitable 
one for his purpose, taking it by preference a little to the left of the 
image of C seen by reflection. The reason of this is that by so doing the 
angle DAO will be made a little over a right angle, so that when a 
second observation is taken from a point further from D, as B, the triangle 
ABC will be very nearly or quite right-angled. By means of the 
milled head Y he then brings the selected object D into coincidence 
with the image of upon a line traced on the center of the mirror M. 
This done, he moves in the direction DA to a convenient point, B, more 
remote from D, and observes once more. The natural object will now 
appear to the right of the re- 
flected image, because the angle 
DBC is less than DAO by the 
amount of the parallax. Coin- 
cidence is established anew by 
turning the ring A, which dis- 
places the object D toward the Fig. 137. 
left. When this is accomplished the graduation under the index of A 
will give a factor, which multiplied into the distance AB will give the 
distance AC. 
38 i A 





594 PARIS UNIVERSAL EXPOSITION. 

The graduation is the inverse of the sine of the parallax, and as, 
assuming in the last figure that B is a right angle — 

A0= ; hence ABxthe inverse of sin:r=AC; 

sin - 

- being taken to represent the parallax. 

To determine the divisions of the graduation, therefore, let ASC, Fig. 137, 
be a section through the summit S of the cone described by the revolving- 
ray, and in this plane, with the radius SA, describe the arc AD, which 
will be equal to three degrees. Suppose the revolving ray to have beeu 
carried by the movement of the ring from A through an angle <p in the 
base of the cone. A plane through the ray perpendicular to AGS will 
cut this plane in a straight line, as SE, and the movement in parallax 
will be the angle ESA. Drop the perpendicular AF upon SE produced, 
and call it j?. Put AE=g, AS=B, and AC= r. 

Then ^>=B sin -. And p=q_ cos (3° — -). 

sin 7t 

Hence E sin it = a cos (3° — -). Andtf = B r^ r- 

1 v ' * cos (3° — -) 

r> ±. . t> sin - r . ' sin - 

But q = r v. s. (p. . . r v. s. <p = B j^- — -. ; or ^ v. s. <s 



cos (3°—-)' E ' COS (3°—: 



t sin 

But ^ = sin ASC = sin 3°. Hence v. s. a> = 



E - - - . ~ w*. ~. , sin 30 cos (30—7:) 

And finally, cos p=.l : — ^ ~ r-(I-) 

J > sm 3° cos (3° — -) 

Also considering that cos (3°— rr)=cos 3° cos - + sin 3° sin -, we deduce 

sin it sin 3° cos 3° v. s. <p _ 0.05227 v. s. <p 

cos - — an JL = 1 — sin 2 3° v. s. <p = i — 0.00271 v. s. <p' ( IL ) 
If <p is given, - may be found from (II.) If - is given, <p may be found 
from (I.) 

By assuming a series of parallaxes, beginning with zero and ascend- 
ing by small differences, the divisions of the ring A may be determined ; 

and the number to be inscribed at each division will be equal to . . 

sm -. 

Thus for -=0o, cos ?=1 and c*=0°. For -=3°, cos cr=0°, and ? ==90° 
For -=1J°, cos 5P = 1—J= J very nearly; and e> = 60°. The multiplier 

for? = 0°is-J— = 1 =co: for -=3° it is 19.1, nearly, and for —IP it is 
sm r. 7 

57.3, nearly; but the parallaxes are chosen in such a manner as to give 

round numbers in the graduation. 

Another mode of making the second observation is the following: 

The instrument is accompanied by a staff graduated to meters and 

fractions, and having a tripod stand to support it. The staff also carries 

sight-vanes. Before the observer leaves station A he turns the ring to 

any graduation which he thinks convenient, and leaving the staff at A. 

retreats toward B, until the coincidence of images, which has been 

destroyed for Aby turning the ring, is accurately re-established. Suppose 



TELEMETRICAL APPARATUS THEODOLITES. 595 

that he had turned to the mark 100 j then he has to measure the distance 
AB, and to multiply it by 100. The distance need not be measured on 
the ground, as the instrument, with the assistance of the staff, furnishes 
the means of measuring it optically. The ring is turned back to the 
mark co, the sight opening is placed parallel to the face of the screw-head 
V, and the telescope is turned with the screw-head uppermost. The staff 
can then be seen by direct vision, and also as displaced by refraction 
through the prism, the imsm not occupying the whole breadth of the 
tube. In the position of the instrument supposed, the two images may 
be so superposed that one of them is the prolongation of the other. 
One of the sight vanes is placed at the top of the staff, and the other is 
moved to such a point that, as seen by refraction, it coincides with the 
first seen directly. The angular displacement is three degrees, and is 
constant for all distances. The staff bears a graduation which tells 
directly the distance AB at which the observation is made. 

The accuracy of measurements made by this instrument is extraordi- 
nary. With a base of twenty meters the error for distances below a 
kilometer is almost imperceptible. Distances of from three to six kilo- 
meters, and even more, have been measured by it, with bases of from 
twenty to fifty meters, with a maximum error not exceeding one-fourth 
of one per cent. 

II.—INSTRUMENTS FOR ANGULAR MEASUREMENT. 

THEODOLITES. 

Though the theodolites exhibited were very numerous, and were 
many of them admirable in workmanship, there was hardly sufficient 
of novelty in the construction of this class of instruments to detain the 
reporter long. Many of the continental theodolites are constructed with 
a view to the measurement of vertical angles from the zenith downward. 
This object can only be secured by placing the telescope at the extremity 
of the horizontal axis, an arrangement which, in measuring horizontal 
angles, involves the necessity of a correction for the center, which is 
laborious and troublesome. It permits, however, observations for col- 
limation to be made from the surface of mercury, as in the case of the 
astronomical transit instrument. To facilitate this observation, Mr. M. 
Balbreck, of Paris, wiiose instruments were among the most beautiful 
of those exhibited, introduces into the ocular, between the two lenses, 
a plane glass mirror with parallel surfaces, which admits of being placed 
at the angle of 45° to the axis, so as to throw the light received through 
an aperture in the tube from a lateral source, directly away from the 
observer and upon the spider lines in the focus. The lines are thus 
brilliantly illuminated, and the eye is not dazzled by the illumination. 
This mirror admits of being displaced to the side of the tube in ordinary 
observation. 

Secretan, Brunner, Rigaud and others, in the French section, Pistor 
and Martens, of Berlin, and Breithaupt, of Hesse-Cassel, all exhibited 



596 PARIS UNIVERSAL EXPOSITION. 

theodolites of admirable construction. Those of Breithaupt presented 
the peculiarity that the graduation of the horizontal circle is protected 
by a glass plate, which also protects the vernier, and which permits the 
divisions to be read while excluding dust and moisture. This construc- 
tion is especially advantageous in theodolites for miners, of which 
this exhibitor presented several patterns. Another peculiarity of Breit- 
haupt's theodolites consists in the use of a differential tangent- 
screw for slow movement. This screw is not a Hunter's screw, in 
which, as is known, one screw works within another of a slightly differ- 
ing thread. On the other hand, in the present case, two threads are cut 
upon the different ends of the same rod. One of these corresponds to 
the thread of the tangent-screw in the common construction, and is that 
by which the slow movement is directly produced. The other runs in a 
fixed nut attached to the clamp-plate, answering to the stud by which 
the common tangent-screw is held, and which serves as its fulcrum. 
These two threads being unequal, the motion imparted to the instru- 
ment is equal to their difference. 

To the statement made above as to the absence of originality in the 
forms of the theodolites exhibited, an exception must be made in favor 
of the " traveling theodolite," invented by Mr. Dabbadie, the African 
explorer, which was shown by Seeretan, and also by Eichens, in the 
French section, and by the Genevese Society in the Swiss. The object 
aimed at in the design of this instrument is to reduce the number of mov- 
able parts as much as possible, to dispense with screws wherever it 
could be done, and to make the whole instrument in the highest prac- 
ticable degree compact and portable. The instrument as exhibited by 
Eichens has a telescope only twenty centimeters (eight inches) long, 
with an objective of one hundred and eighty-five millimeters (seven and 
one-half inches, nearly,) focal length, and a clear aperture of twenty-five 
millimeters, (one inch.) For the sake of commanding a large field of 
view, the magnifying power is carried only to eight times. The chief 
peculiarity of this instrument consists in the fact that the telescope has 
no motion in altitude, but is firmly supported in a horizontal position, 
with only a rotary motion around its axis of figure. The expedient by 
means of which vertical angles are measured with it is the following: 

dabbadle's theodolite. 

Referring to the figure annexed, it will be seen that to the telescope 
tube is attached, immediately in front of the object glass, o large isosceles 
rectangular prism, having one of its side faces perpendicular to the axis 
of the instrument. The observer therefore places the instrument so that 
the telescope axis is at right angles to the vertical plane in which the 
object is situated of which the altitude is to be measured; and by turn- 
ing the telescope in its supports the image of the object is seen by 
reflection in the prism. At the extremity next the eye. the telescope 
carries a vertical circle of ten centimeters (four inches^ radius, divided 



THEODOLITES LEVELING INSTRUMENTS. 



597 



centesimally, and this is read by a vernier to one one-hundredth part 
of a degree. The horizontal points of the limb are not determinable by 
direct observation ; but the zen- 
ith and nadir points are found 
with facility. For the nadir 
point resort is had, as usual, to 
reflection from the surface of 
mercury. For the zenith, a 
trough filled with water, and 
having as a bottom a plate of 
glass with parallel surfaces, is 
placed over the object end of 
the telescope. The upper sur- 
face of the water serves as a 
reflector. The zenith and nadir 
points being found, their circle 
readings, if correct, will differ 
by a semi-circumference. And 
it is easy at any time to verify 




to 

Dabbadie's Theodolite. 



their accuracy by observing the zenith distance of any object, and also 
that of its image seen by reflection in mercury, and adding the two. 
The sum should be a semi-circumference. The horizontal circle is of 
the same diameter as the vertical. The movements, both horizontal 
and vertical, are effected without tangent-screws, the rack and pinion only 
being used. Two cross-levels serve for the adjustment of the plane of 
horizontal movement. Mr. Eichens has also added a small compass to 
the instrument exposed by him. Nothing could be in appearance more 
convenient than this instrument for the use of the scientific traveler 
who desires to make observations upon the heights of mountains, the 
breadths of streams, or other matters of geographical or geodetical 
interest. 



LEVELING INSTRUMENTS. 

Leveling instruments of excellent construction were exhibited by Mr. 
Gravet Tavernier of Paris, and by Mr. 1ST. A. Pierson, in which the levels 
admit of reversal without being detached; a very useful provision against 
accidents. In the Portuguese section there appeared also an instrument 
of this class, in which two telescopes parallel to each other, but looking 
in opposite directions, are so disposed as to turn about a horizontal axis 
parallel to both, by which arrangement either may be brought upper- 
most, and the backsights and foresights may be made without reversal. 
This construction is favorable to expedition, but whether it is equally 
so to accuracy remains to be proved. A peculiarity was noticed also in 
the leveling instruments of Breithaupt of Oassel, in which the supports 
of the telescope are hardened steel knife edges, resting on plates also of 
hardened steel. 



598 



PARIS UNIVERSAL EXPOSITION. 



REFLECTING INSTRUMENTS. 

Among the reflecting instruments exhibited, the most noticeable were 
the circles of Messrs. Pistor and Martens, of Berlin, which by the 
arrangement of the fixed and movable mirrors very considerably increase 
the extent of angle commanded by the instrument. This arrangement 
is illustrated in the accompanying figure, in which c d is the index glass, 
e the horizon glass, andy the telescope. The horizon glass is not a sil- 
vered mirror, as in the common sextant, but an isosceles rectangular 
ruisin of which the diagonal face serves as the mirror by total internal 
reflection. In order that objects beyond the horizon glass may be seen 
by direct vision, the height of the prism perpendicular to the plane of 
the instrument is only half that of the index glass, and is such as to 
intercept only one-half the light coming from the object directly observed 
to the objective of the telescope. It is a little remarkable that the com- 
mon sextant should have continued to be so long constructed with a 
horizon glass half silvered and half unsilvered, when the unsilvered 
portion is not only useless, but is a positive disadvantage. 

Sextants are also constructed by Messrs. Pistor & Martens on the 
same principle; and with these the measurement of angles is carried up 
to 180 degrees. This cannot be done by holding the instrument in the 
same position throughout the whole range. It will be obvious, by refer- 
Fig. 139. ring to the figure of the circle here given, 

that after reaching a certain magnitude of 
angle, which depends upon the relative po- 
sitions of c d and e, the rays from the object 
seen by reflection will begin to be cut off 
by the prism e. When this is the case, the 
sextant is turned with the limb uppermost, 
and the higher angles are read upon a 
different part of the limb. In the circle 
this expedient cannot be employed except 
by abandoning one of the verniers. If, for 
instance, in the figure, the upper index arm 
should be removed, the lower arm could 
traverse nearly the entire limb. As the 
sextants are constructed, all angles up to 
140 degrees are measured with the instru- 
ment in the usual position. For angles 
; between 110 degrees and ISO degrees the 

Pistor & Martens's Circle. instrument is inverted, and the graduation 
begins at a new point about GO degrees farther along the limb, reading 
in a direction opposite to the first. Where the angle approaches ISO 
degrees, the head of the observer begins to interfere. This case is 
provided for by adding a diagonal eye-piece to the telescope, which per- 
mits the observer to put himself out of the plane of observation. 




EEFLECTING INSTRUMENTS SEXTANTS. 599 

LAURENT'S SEXTANT FOR STELLAR OBSERVATIONS. 

Another modification of the sextant deserving of attention was exhib 
ited by Captain Albert Laurent, formerly of the French naval service, 
and at present commander of the transatlantic steamer Imperatrice 
Eugenie. Captain Laurent observes that navigators lose, for the most 
part, the benefit of observations of stellar altitudes, in consequence of 
the difficulty of making the contacts of the image of the star with the 
horizon. His remedy for this difficulty is to elongate the image of the 
star in a direction perpendicular to the plane of the observation, whereby 
the object is made more conspicuous, and the facility of observation is 
greatly increased. The elongation of image here spoken of is produced 
by placing a cylindrical lens with its axis of figure parallel to the plane 
of the instrument, and its optical axis also parallel to the same plane 
and coincident with the direction of the rays proceeding from the star. 
The focal length to be given to the cylindrical lens depends upon the 
degree of elongation which it is desired to give to the star, on the focal 
lengths of the glasses of the telescope, and on the distance between the 
lens and the objective of the telescope. The inventor finds that an appa- 
rent angular elongation of the star equal at the eye to five degrees is 
about the most satisfactory; but as the observer sees only one-half of 
the total elongation, the lens ought to be capable of producing a length- 
ening effect equal to ten degrees. 

As there is a practical advantage in making the distance between the 
lens and the objective of the telescope as great as possible, Captain Lau- 
rent has placed his telescope and his horizon-glass as near the graduated 
limb, and as far from the center of the instrument, as convenience in use 
will allow. For the sake of increasing the light, he has greatly enlarged 
the diameter of the telescope objective. This, in the instrument exhib- 
ited, must have been not less than four or five centimeters — between one 
and two inches, and nearer the latter. The unsilvered part of the hori- 
zon-glass is also suppressed, an improvement the value of which has 
been alluded to above. 

It is asserted by Captain Laurent that the observations of the alti- 
tudes of stars made with the same instrument, with and without the 
elongating lenses successively, show an advantage as to accuracy of 
results in favor of his improvement in the ratio of five to one. He 
adds, " Besides this, the new method permits the observer to note those 
altitudes on which he can count with certainty; while formerly there 
remained in the observer's mind a doubt and uncertainty which took 
away all confidence. It could not be otherwise, since frequently there 
presented itself a difference between two successive altitudes of fifteen 
to twenty minutes, without there being any ground for preferring one 
of these observations rather than the other." 

This new form of sextant was devised with especial reference to obser- 
vations for latitude; but the inventor believes it also quite as well adapted 



600 PARIS UNIVERSAL EXPOSITION. 

to determinations of longitudes, whether by observing the altitudes of 
the planets, or of bright stars, or by measuring lunar distances. Expe- 
rience can only decide on the justice of this claim. In the mean time he 
informs us that the instrument has been recently introduced on board 
of several of the transatlantic steam-packets, with results which have 
much surpassed his expectations. "It has always been possible," he 
says, "to determine the latitude [with this instrument] with rigorous 
precision, however sombre might be the horizon, whether by the meri- 
dian altitudes of stars or by that of the pole star. The application to 
the determination of longitudes by stellar altitudes has furnished results 
remarkable for their exactness. It has been possible, by the aid of noc- 
turnal observations, to trace upon the chart the vessel's route, not only 
from hour to hour but from minute to minute, and consequently to make 
land or to traverse the most dangerous waters by night, with an extreme 
security." This is perhaps saying too much; but at any rate there can 
be no doubt that the instrument is well worth the attention of naviga- 
tors. 

DAVIDSON'S SPIRIT-LEVEL SEXTANT. 

Still another improvement of the sextant was exhibited in the depart- 
ment of the United States by Mr. George Davidson, of the United States 
Coast Survey. It may be said to be, as to its object, the converse of that 
of Captain Laurent, just described, inasmuch as the aim of that inge- 
nious inventor is to make observations on the horizon as useful as pos- 
sible, while Mr. Davidson proposes to be rid of them altogether. More- 
over, horizon observations are only possible at sea, and are unavailable 
to the geographical explorer on land. The artificial horizon is a some- 
what troublesome substitute, cumbrous in transportation and subject to 
provoking derangements. And of its availability in use, when in good 
condition, in exigencies of frequent occurrence with the traveler. Mr. 
Davidson furnishes the following illustrations: "The sun may be too 
high for observing double reflections with the ordinary sextant; the sun 
or a mountain may be too low to admit of available reflection in the arti- 
ficial horizon; and in particular, these means positively fail when from 
any elevated point the traveler wishes to measure the depression of 
some object, as of the sea horizon, by which to determine his elevation 
or distance, knowing one of them; or, knowing the distance of another 
and lower mountain, to determine the difference of elevation. We have 
encountered all these difficulties, and also the less frequent one of falling 
in with a reef at night with the stars visible, but the sea horizon totally 
obscured in darkness." 

Mr. Davidson's improvement consists in the use of an observing tube 
to which is attached, on the top, a small spirit level, the bubble of which 
is seen by reflection, in a manner which Fig. 140 will serve to explain. 
The observing tube is G G, which is supported by the exterior tube C : 
and this in turn is secured to the sextant by the screw M. which cow. 



DAVIDSON 'S SPIRIT-LEVEL SEXTANT. 



601 



nects with the ordinary telescope support. The ends of the tube G G 
are closed by plane glasses; a precaution apparently unnecessary. At 



Fiff. 140. 



Fig. 141. 




W, on the top of the tube, is 
an opening, which permits the 
bubble of the level S to be seen 
by reflection from the mirror 
E, placed at an angle of forty- 
five degrees to the axis of the 6 

tube. As the level will be too Davidson's Spirit-level Sextant. 

near for distinct vision, a convex lens, L, is introduced into the tube 
between the mirror E and the eye; and this, by means of a screw-head 
exterior to the tube, may be advanced or withdrawn to accommodate 
different eyes. As the mirror E must not be permitted to cut off the 
view of the objects under observation, it has a breadth only equal to 
one-half the diameter of the tube. The lens L, also, is but a semicircle. 
All the half of the tube next the face of the instrument is clear. Fig. 
141 is a cross -section, and shows this arrangement. It shows also that 
the spirit level is unsymmetrically placed on the top of the tube, being 
directly over the outer half, or that which is furthest from the face of 
the instrument. 

The adjustment of this level is made either by changing the angle 
of the reflector, or by moving the frame carrying the cross-wires, or by 
elevating one end of the level itself; and it consists in making the image 
of the cross- wires bisect the image of the bubble when a distant object 
in the same horizontal plane and seen through the unoccupied half of 
the tube appears on a level with the image of the cross-wires. This 
adjustment is readily effected on land, may be made by means of the 
level itself, and is not easily deranged. Should it, however, become 
necessary to adjust the level at sea, the image of the cross-wires, when 
it bisects the image of the bubble, is made to appear on the same line 
with the visible horizon; and the correction for the dip of the horizon 
at the given height of the observer's eye is applied to all observed alti- 
tudes and depressions. 

The index error may be determined when the level is adjusted on 
land, and used as a constant quantity for a not very extended series of 
observations, or it may be determined at sea whenever the horizon is 
visible, by observing the depression of the horizon and taking the dif- 
ference or sum of the observed result and the computed dip for the 
index error. 

The operation of making an observation for the altitude or depression 
of any object at sea or on land is as follows : Secure the level in its proper 
place on the instrument and hold the sextant in the usual manner, with 
the plane of its face in the vertical plane passing through the object and 
the observer. Looking through the tube, move the vernier arm until 
the image of the object is seen through the unoccupied half of the tube, 



602 



PARIS UNIVERSAL EXPOSITION. 



and bring that image into the same horizontal line with the image of the 
cross-wires at the time it bisects the image of the bubble, and if necessary 
note the time by chronometer. If the sextant and the level are in adjust- 
ment, the reading on the limb indicated by the vernier is the observed 
altitude or depression of the object. 

Observations at night require the bubble to be illuminated. This 
niay be done by means of a lamp ; but Professor Erazer, of Philadelphia, 
has made the ingenious suggestion that a small tube containing phos- 
phorus in oil may be placed over the level, into which the admission of 
air, when necessary, will produce all the illumination which the purpose 
in view requires. 

Some j udgment may be formed of the performance of this instrument 
from the following statement of actual observations made by Mr. David- 
son in I860. 

Latitude from cir cummer idian altitudes of the sun with sextant and spirit-level horizon. 
Observations of November 11 commenced 5 minutes 46 seconds before apparent noon, and 
ended 13 minutes 18 seconds after noon. November 12 commenced 7 minutes 23 seconds 
before, and ended 5 minutes 55 seconds after apparent noon. 





November 11, 1865. 








November 12, 1865. 






w 


(7) 





J0_ 


Deg. 


Min. Sec. 


Deg. 


Min. 


Sec. 


Des. 


Min. See. 


Des. 


Min. 


Sec. 


39 


59 18 


39 


57 


14 


39 


60 12 


39 


54 


19 




55 55 




57 


36 




59 28 




56 


37 




57 05 




57 


18 




57 51 




56 


31 




56 52 




58 


41 




57 39 




58 


13 




57 55 




59 


43 




56 01 




57 


51 




55 5-2 




61 


27 




56 59 




58 


29 




58 41 






-- 




58 54 




59 


01 


Means 39 


57 23 


39 


58 


38 


39 


58 09 


39 


57 


17 



These reductions have been unnecessarily made to seconds of arc 
that the actual working of the instrument may be seen; the probable 
error of one observation deduced from these series is one minute of arc. 
and the probable error of the mean of all the observations is thirty-five 
seconds of arc. This, of course, excludes whatever constant errors may 
have existed. 

Mr. Davidson does not seem to have been aware that the expedient 
employed by him had ever been resorted to for a similar purpose before. 
In the Exposition of 1862 there were exhibited a number of modifications 
of the sextant designed to supersede the use of the artificial horizon, 
two of which resembling this are briefly described by the jury. Having 
stated that the noA'elties of this character present in the Exposition are 
reducible to three classes, viz : first, a spirit level, of which the bubble 
is reflected in the field of view ; second, a pendulum either supported 
freely or immersed in fluid, having a horizontal arm that projects along 



SEXTANTS — NAUTICAL COMPASSES. G03 

the line of sight; and, third, two independent floats with cross-arms, 
swimming in the same vessel of ilnid ; the jury go on to say that, in the 
first class, Messrs. Elliott Brothers, of London, " exhibit an arrangement 
of this kind, that is exceedingly light and compact. It is inserted with- 
in the eye-tube of an ordinary sextant telescope, and gives a remarkably 
clear bubble in the same field of view with the reflected object;" and 
that Mr. T. O. Buss, also of England, exhibits a similar construction, 
which is however somewhat more bulky, showing the bubble to the naked 
eye with much sharpness." 

The pendulum contrivances mentioned by the jury were two ; the first 
being " merely a small pendulum with two light arms which can be 
attached in front of the horizon glass, the arms appearing to coincide 
when the eye-tube is held horizontally;" and the second being " a mas- 
sive appendage, consisting of a metallic chamber filled with oil in which 
the pendulum is suspended by a thin steel spring from a perforated axis 
through which the sight is taken, the turned up edge of the horizon- 
tally projecting arm appearing as a permanent horizon. The free move- 
ment round the perforated axis causes the edge to be parallel to the 
horizon, and that of the steel spring causes it to maintain a constant 
altitude." 

In the instruments employing floats instead of a pendulum, (there was 
only one of this kind) an iron vessel containing mercury in two separate 
but communicating chambers, having glass walls, was attached to the 
face of the sextant. The line of coincidence of the floats when at rest 
gives the horizontal line. All these mechanical expedients are mani- 
festly inferior to the optical contrivance of Mr. Davidson; who must, 
however, share the credit of the invention with the British inventors who 
brought it forward as early at least as 1862. 

IIL-NAUTICAL COMPASSES. 

Among instruments of this class there were exhibited one or two 
rather interesting novelties. In the Norwegian section appeared a ship's 
compass, the invention of Mr. B. F. de Wedel-Jarlsberg, designed to 
furnish automatically a kind of record of the course maintained by the 
vessel during any determinate period of time. The card, or rose, of this 
compass, carries at the center a small funnel communicating with a tube 
which runs from center to circumference and turns downward at the 
extremity. This tube revolves with the rose. Immediately beneath the 
extremity is a trough occupying the whole circumfrence of the instru- 
ment, and divided by partitions into compartments corresponding to the 
several points of the compass. Above the instrument is placed a kind 
of hopper containing small leaden balls, one of which is released every 
minute by a chronometric apparatus, and falling into the funnel is 
directed into the compartment which corresponds to the course which 
the vessel is at the moment pursuing. At the end of the time the num- 



604 PARIS UNIVERSAL EXPOSITION. 

bers of balls in the several compartments will furnish the means of ascer- 
taining the mean course of the ship, and also the greater or less regu- 
larity with which this course has been maintained. It is said that this 
compass has been found useful in actual navigation, and it is certainly 
worthy of attention by those whom it most concerns. 

A nautical compass invented by Mr. E. S. Bitchie, of Boston, and 
exhibited by Mr. Duboscq in the French section, was noticeable as being 
a much more important improvement than the foregoing. The disad- 
vantages of the common compass are three-fold, consisting, first, in 
the too great pressure upon the pivot, occasioned by the weight of the 
needle and card, and the consequent wear ; secondly, the resistance 
opposed by friction to the directive force of the earth's magnetism ; and 
thirdly, the agitation and oscillations produced by the motion of the 
vessel. Mr. Eitchie's compass is designed to provide a remedy for all 
these disadvantages. It presents to the eye an equal armed cross formed 
of hollow cylinders of thin metal, and carrying attached to the ends of 
the arms of the cross a circular ring, on which are inscribed the usual 
divisions of the compass ; the whole being inclosed within a cylindrical 
box with a glass top, filled with an uncongealable liquid and suspended, 
as usual, in gimbals. The needle is contained in one of the two cylin- 
ders forming the cross ; and these cylinders, containing only air, con- 
stitute a buoy, of which the weight is so adjusted that the pressure of 
the system upon the pivot is reduced to a few milligrams. The dete- 
rioration from wearing is consequently, for long periods of time, almost 
insensible ; and the resistance of friction to the traversing of the needle 
is a minimum. But perhaps a more important advantage, as it regards 
the preservation of the points in contact, and as it regards the steadi- 
ness of the indications of the needle, results from the fact that the whole 
moving system is of so nearly the same specific gravity as the liquid in 
which it is immersed as to make both participate equally in the move- 
ments caused by the rolling and tossing of the vessel, or the working of 
the engine, and to allow of no differential motion between the needle 
and its pivot. Thus a serious source of unsteadiness and of wear is 
effectually removed. In order to prevent any injurious effect from fol- 
lowing the changes of temperature to which the instrument is liable to 
be subjected, there is attached to the bottom of the box a small metallic 
chamber with elastic walls, like the box of an aneroid barometer, keep- 
ing the compass-box always full but maintaining the inclosed liquid at 
a coustant pressure. This instrument has been thoroughly tested on 
board of many American vessels, and the numerous certificates of its 
admirable performance, and of its great superiority to the ordinary 
compass, especially in rough weather, which have been addressed to the 
inventor by navigators of experience, leave no doubt of the great prac- 
tical value of the improvement. 



APPARATUS FOR DEEP-SEA SOUNDING. 605 

IV.— DEEP-SEA SOUNDING. 

The difficulty and uncertainty attending* deep-sea soundings with the 
ordinary lead and line, have led to the suggestion of many devices 
designed to secure a higher degree of accuracy. The sounding line, 
drifting under the influence of the currents which prevail far beneath 
the surface of the sea, will often continue to run out long after the lead 
has struck the bottom, so that the moment of striking cannot be detected; 
and the depth inferred from the operation will inevitably be in excess of 
the real depth. Moreover the resistance opposed to the descent of the 
lead by the friction of the line in the water continually increases as the 
length of the line increases, and the velocity of the descent correspond- 
ingly diminishes ; so that, at the depth of about two thousand fathoms, 
this resistance becomes equal to the gravitating force, and the descent 
is arrested altogether. This difficulty cannot be effectually overcome 
by indefinitely increasing the weight, for the weight must not exceed 
the tensile strength of the line ; otherwise the line itself will ultimately 
part and the lead will descend without it. The extent to which the 
results of deep-sea soundings are affected by the considerations here 
mentioned, and the absolute impossibility of receiving as correct the 
reports which have from time to time been made by navigators of casts 
of the lead without finding bottom to depths of five, seven, and even 
nine miles, were first, as it is believed, pointed out by Professor W. P. 
Trowbridge, now of New York, in the Reports of the United States 
Coast Survey, and in the American Journal of Science and Arts, in 1858. 

TROWBRIDGE'S DEEP-SEA APPARATUS. 

Professor Trowbridge proposed a simple and very effectual mode of 
overcoming all the difficulties which have hitherto perplexed the prob- 
lem of deep-sea sounding, and of reaching in all cases results entirely 
trustworthy. This consists in inclosing the line itself, wound in balls 
which uncoil from the center, in a hollow cylindrical case, and sending 
it down along with the lead ; the end only being secured to the boat 
occupied by the observers. The force required to uncoil the line is 
entirely insensible, there is no dragging of the line through the water, 
and the descent of the lead is rapid and uniform from first to last. Lat- 
eral currents will have no influence on the vertical velocity. What this 
velocity should be may be calculated theoretically, and, for greater 
security, what it actually is may be determined, once for all, experi- 
mentally. After this, the time observed to elapse between the throwing 
of the lead and its striking the bottom, becomes an accurate measure of 
the depth. It is necessary, therefore, that the observer should be able 
to note exactly the moment of impact of the plummet upon the bottom. 
In order to do this the sounding line of Professor Trowbridge's appa- 
ratus contains a fine insulated wire connected with an alarm or with a 



606 PARIS UNIVERSAL EXPOSITION. 

chronoscope in the boat, and also with a battery. The impact of the 
lead on the bottom completes an electric circuit, and the time required 
thus becomes known. This part of the apparatus was invented as early 
as 1845; but inasmuch as the descent of the lead, in the old mode of 
sounding, was not at all uniform, the contrivance had no other value 
except to notify the observers at what moment they might begin to 
haul back the line. Moreover, the great strain upon the line in that 
mode of practice had a tendency to break the insulation, and the method 
was employed no further than to test its practicability. 

It is to be observed, however, that the really important part of Pro- 
fessor Trowbridge's invention, which consists in the expedient by which 
the resistance opposed by the friction of the line to the descent of the 
lead is prevented, is not dependent for its practical availability upon the 
observation of time, or upon the use of electricity. A method was both 
proposed and employed by him for determining depths by attaching to 
his apparatus containing the line, a pair of Saxton's improved " current- 
meters." The current-meter of Saxton is a delicately pivoted helix- 
which is turned by the water through which it passes, as a boy's wind, 
mill is turned by the air, and which records the number of its revolu- 
tions upon a set of registering dials. In sounding, it is necessary to 
employ two such helices, turning in opposite directions, for the purpose 
of eliminating any error which might arise from the rotation of the 
whole apparatus in consequence of the twisting of the line or other dis- 
turbing cause. It is necessary, also, to provide that so soon as the 
plummet makes contact with the bottom of the sea, the helices shall be 
thrown out of gear with their registers. On hauling them back, the 
depth from which they have been recovered will be ascertained by tak- 
ing the mean of the two records. 

Helical current-meters have been employed in sounding by the ordi- 
nary method ; and in fact, for sounding in deep seas, they have been 
regarded as indispensable, in consequence of the great errors likely to 
arise from the drifting of the line, or from its continuing to run out 
after the bottom has been reached : but the form of helix employed has 
been that known as Massey's, in which the wings are attached to a 
bulky central axis, and of which the indications have not been found 
always consistent with themselves. The current-meter of Saxton per- 
forms in a manner very much more satisfactory. 

In sounding at extreme depths by this method, or indeed by any 
method, it need hardly be said that the plummet itself cannot be recov- 
ered ; for in hauling back, the line has to overcome the friction of its 
whole length as well as the weight of the lead : and since this weight 
alone is all that it is able to bear, it necessarily parts when the strain 
is doubled. But by an automatic detachment of the sinking weight at 
the bottom, the lead may be so lightened that the apparatus for regis- 
tration may generally be brought back safely. A contrivance for effect- 
ing such a detachment was first introduced by Lieutenant J. M. Brooke. 



APPARATUS FOR DEEP-SEA SOUNDING. 607 

of the United States navy, in 1857, which may be found described in 
" Maury's Sailing Directions," published under authority of the Navy 
Department in 1858. The object which Lieutenant Brooke had in view 
was to obtain specimens of the deposit at the bottom of the sea. In 
order to do this, the sinker employed was a thirty-two pound shot, per- 
forated through the center. Through this perforation passed an iron 
tube projecting below, and into the extremity of the tube were intro- 
duced a number of quills, which, as the tube struck the bottom, became 
filled by the pressure, and were brought safely up filled with the ooze. 
Another apparatus, very much resembling this, was invented by Com- 
mander B. F. Sands, noAV Commodore Sands, in charge of the United 
States Naval Observatory, about the same time. In this case the design 
was to permit the recovery of the Massey helix. 

SOUNDING WITHOUT A LINE. 

The possibility of sounding without a line has occupied the attention 
of many persons interested in this subject. All such schemes involve, 
of course, the ascent of the apparatus by its own buoyancy, after the 
detachment of the sinking weight. But the difficulties in the way of 
their practical success have been generally regarded as too great to be 
overcome. In the first place, no solid buoy is available for the purpose, 
since there is no solid which is buoyant in water, and which is at the 
same time free from liability to be compressed in the deep sea to a den- 
sity so great as to prevent it from returning. In the next place, no hol- 
low buoy of metal will answer, since in order that a metallic vessel may 
be strong enough to resist collapse, it must be made too thick to be 
buoyant. Glass has been proposed as a material suitable for the pur- 
pose, by the inventors of an apparatus presently to be mentioned j and 
these gentlemen state that spherical glass buoys have been subjected by 
them to a pressure of seven tons to the square inch, without being 
crushed. Such a pressure corresponds to a depth of about six miles • 
and accepting the statement as correct, we may regard this part of the 
problem as having been practically solved. 

There are other difficulties, however, of which the same remark cannot 
be made. It will be of no avail that the sounding apparatus returns to the 
surface, unless it brings back with it some trustworthy indication of the 
depth to which it has been submerged. Such an indication, it has been 
supposed, might be afforded by a pressure-gauge adapted to register the 
maximum hydrostatic pressure to which the apparatus has been sub- 
jected. There is room, however, for serious doubt whether any form of 
gauge which has yet been suggested, can be relied on satisfactorily to 
fulfill this condition. This question has occupied much attention on the 
part of those who have studied the subject of deep-sea sounding, and 
the conclusion has generally been unfavorable. It is probable that the 
experiments of Perkins, published in the year 1820, first suggested the 
possibility of ascertaining depths by a method founded on the com pre s- 



608 PARIS UNIVERSAL EXPOSITION. 

sibility of water ; but the fact that a change of temperature of a single 
degree centigrade produces a much larger change in the volume of 
water than an increase or diminution of pressure by an entire atmos- 
phere, and the additional fact that the law governing the relations of 
temperature to volume is inverted between thirty -two and forty degrees 
Fahrenheit, have discouraged most persons from attempting to follow 
out this idea. In the Exposition of 1862, nevertheless, a deep-sea pres- 
sure-gauge was exhibited by Mr. H. Johnson, a British inventor, which 
was essentially a reproduction of the form of apparatus originally 
devised by Mr. Perkins. The jury remark of it that, in practice, a cor- 
rection must of course be applied for change of temperature. The 
difficulty is to know what is the temperature at the greatest depth, 
since that is not necessarily the minimum. 

But further than this, it is to be taken into account that the compres- 
sibility of water is itself variable with the temperature, being, according 
to the most recent determinations by Grassi, fifty-one and a half one- 
millionths of the total bulk per atmosphere, at 1.5° 0, and only forty-six 
one-millionths at 18° 0, becoming still less as the temperature rises. In 
the absence of any knowledge of the actual temperature at the bottom 
of the sea, this circumstance alone, and without reference to the fluctu- 
ations of volume occasioned by thermal changes, would render the deter- 
mination uncertain to the extent of possibly one-tenth of the entire 
depth. As a security against this error there is no protection but that 
which is afforded by the doubtful indications of the minimum thermom- 
eter. 

An additional objection is found in the consideration that the time 
which elapses between the dispatch and return to the surface of the 
sounding' apparatus will be so great that, except where there are no 
subaqueous currents — that is to say, except under conditions which 
nowhere exist — the point at which the float will reappear will be very 
far from that occupied by the observers. It is hardly necessary to insist 
on the difficulty of detecting a very small object which may be afloat 
upon the waves anywhere within a radius of two or three miles. It is a 
necessity of the case that the object should be small, for whatever 
increases its bulk diminishes relatively the accelerative force with which 
it ascends, protracts the duration of its absence, and adds proportion- 
ally to the extent of the area over which it must be sought for. It has 
occurred to every one who has thought upon this subject, that some- 
thing might be gained to the conspicuousness of the object, by providing 
it with reflecting surfaces, analogous to those of the scintillating signals 
used in geodetic operations 5 but after making every allowance for the 
degree of possible effectiveness to be anticipated from this expedient, 
practical men have been inclined to consider the objection fatal. 

How far this conclusion is reasonable, may be inferred from the fol- 
lowing considerations. The time occupied by the apparatus in the 
descent and return is ascertainable by applying the formula; of Dubuat 



APPARATUS FOR DEEP-SEA SOUNDING. 609 

expressing the laws of motion of sinking bodies as deduced from actual 
experiment. Applying these form ulae to the questiou under consideration, 
Professor Trowbridge (American Journal of Science, 1858) has shown 
that, in the case of a sphere, the velocity becomes very soon uniform — 
for a cannon shot of thirty-two pounds, for instance, in less than three 
seconds — and that the value of this uniform velocity will be expressed 
by the equation, 



v sr> 



SD 

In which V represents the velocity sought, in feet ; W the weight in 
water of the body expressed in pounds avoirdupois ; S the horizontal 
cross-section in square feet or fractions ; and D the density of the liquid 
expressed by the weight avoirdupois of a cubic foot ; while g represents, 
as usual, the force of gravity. For a thirty-two pound shot W will have 
an effective value of 23.38 pounds, and S will be 0.21 square foot. D in 
sea- water will be 64.2 pounds, and g is 32.189 feet. Substituting these 
numbers in the formula, the sinking velocity will be found = 16.21 feet. 
In order to secure this velocity or a greater against the resistances of 
the sounding apparatus arising from its buoyancy and friction, the 
weighf must be increased. Taking it, however, at sixteen feet, the 
apparatus will sink to the depth of five miles in twenty-seven and a half 
minutes — say half an hour. The return will be much slower, since the 
ascending force will be equal only to the weight of the water displaced 
by the buoy, diminished by its own weight and that of the attached 
apparatus in water. Supposing the buoy to have the same dimensions 
as the thirty-two pound shot, or a diameter of six inches and a fifth, it 
will displace a weight of water equal to 4.621 pounds. Its thickness 
must be sufficient to resist the crushing pressure of the deep seas — say 
at least half an inch. The weight in water of its solid material will, 
therefore, be more than a pound and a half, which will diminish its 
effective buoyancy to three pounds ; and to this reduction must be added 
the weight in water and the factional resistance of the attached appa- 
ratus, which will be equivalent, perhaps, to a pound additional. The 
buoy, therefore, will have an upward tendency which may be measured 
by a constant pressure of two pounds. Substituting this for W in the 
formula foregoing, we shall find that the uniform ascending velocity will 
be four feet and three-eighths $ and the time of ascent from a depth of 
five miles will be one hour and forty minutes. Thus the total time of 
descending and ascending in a sea of the depth supposed, will exceed 
two hours. Daring so long a period, the apparatus could not fail to 
drift very widely. 

THE BATHOMETER. 

In the present Exposition an instrument has been exhibited in the 
American section, by Messrs. Sidney E., and G. Livingston Morse, of 
39 i A 



610 PARIS UNIVERSAL EXPOSITION. 

New York, which is called by them a bathometer, and which, as its 
name implies, is designed to determine the depths of the waters of deep 
seas. The instrument is described by its inventors in the words following : 

a This invention consists in general terms in measuring the depth of 
water by the compression of a fluid or fluids contained in a vessel sunk by 
a weight, which is automatically detached from the rest of the apparatus on 
striking bottom, allowing the vessel audits other accompaniments to be 
raised by a buoy, the apparatus being sunk without any connection with 
a line, and the buoy being provided with a signal to enable the operator 
to discover it when it ascends to the surface of the water. 

" In carrying out this invention, take a glass bottle, say about five or 
six inches long, and of such interior diameter that its capacity exclusive 
of any solid substance and of the mercury and air it may contain, shall 
be about five cubic inches ; take also a glass meter tube about seven or 
eight inches long, open at both ends, with a bore of about one-fifth of 
an inch in diameter ; let this tube be swelled near the upper end and 
the swelled part ground into a stopper to fit the neck of the bottle ; 
pour into the bottle mercury to a level with the lower orifice of the 
meter tube and enough more to fill the meter tube once 5 then fill the 
bottle with water and insert the meter tube so that the swelled part or 
ground glass stopper shall be fitted perfectly tight into the neck of the 
bottle ; take then a thin India-rubber tube five or six inches long and 
draw it over the outer end of the meter tube and fasten it, fill the rub- 
ber tube with water, and fasten it by winding and tying a cord around 
the tube 5 it will then form a bag of water, and it should be long enough 
to hold a quantity of water at least sufficient to fill the meter tube once. 
A scale is to be adapted to the meter tube. When the instrument is 
ready for operation the water or lighter fluid will completely fill the meter 
tube. If the instrument is now sunk in deep water the external press- 
ure of the water as it descends will cause the fluids in the India-rubber 
bag, the meter tube, and the body of the vessel to contract, and will 
force the water in the meter tube through the mercury into the body of 
the vessel to supply the vacancy caused there by the compression of its 
contents. On the return of the instrument to the surface the expansion 
of the fluid or fluids in the body of the vessel under the relaxation of 
the external pressure during the ascent will force the mercury into the 
meter tube to the amount of their greatest compression, thereby indi- 
cating the degree of that compression and by inference the depth to 
which the instrument has descended. The instrument is rendered more 
sensitive and more applicable for measuring depths not exceeding 500 
feet by the introduction of a minute quantity of air or other elastic 
fluid into the vessel containing the liquids. The liquids can easily pass 
each other in the bore of the meter tube, thereby enabling the operator 
to restore them to their original position for a new operation merely by 
turning the instrument. A bag of India-rubber or other suitable flexi- 
ble material is attached to the outer end of the meter tube for the pur- 



APPARATUS FOR DEEP-SEA SOUNDING. 611 

pose of preserving tlie exact quantities of the fluids in the vessel as at 
first adjusted and of enabling the operator by pressure upon the bag to 
discharge the contents of the meter tube into the vessel, and therefore 
to use a meter tube of small bore. A buoy and weight is attached to 
the instrument by any suitable self-detaching device, so that when the 
instrument or its appendage touches the bottom the weight shall be 
detached and allow the buoy to carry the instrument to the surface, 
thereby dispensing with a line. The submerged buoy is released by 
causing a small weight attached to the long arm of a lever to support 
on the short arm a larger weight which sinks the buoy till the smaller 
weight by touching the bottom is supported thereon, thus causing the 
short arm no longer counterpoised to fall and discharge the weight. A 
rod or pole is attached to the instrument, so that on its return to the 
surface of the water it will attract attention at a distance, so as to facili- 
tate the recovery of the apparatus of which it forms a part. 

" The upper end of the rod should be prepared with small pieces of 
bright tin, polished metal, silvered or colored glass, or other substances 
which will reflect the light and attract attention from a distance. For 
greater accuracy in deep-sea soundings the bathometer should be sur- 
rounded by melting ice to keep the bottle and its contents at (32° F) 
a fixed temperature. The buoy used is of glass, this being about the 
only material which will resist the immense pressure of a column of 
water miles in height and retain its buoyancy. A glass sphere in the 
United States Patent Office has withstood the pressure of seven tons on 
the square inch. It floats more than half out of water." 

In this description mention is made of only a single buoy, but the 
figure of the apparatus which accompanies the description represents 
three buoys of spherical figure inclosed one above another in a cylin- 
drical case having rounded ends. The model buoy deposited at the 
Patent Office has a diameter of about five inches. According to the 
foregoing statement of the inventors, this sphere floats half out of water. 
Its force of buoyancy is therefore equal to half the weight of the water 
which it displaces when submerged, and this will be expressed by the 
equation F=Jx \-(Px 64.2 =1.216 pounds. Multiplying this by three, 
we have as the total ascending force of the three spheres, 3.648 pounds, 
which is to be diminished by the weight in water of the apparatus to be 
raised and its enveloping cylinder, and the friction of the water upon 
the extended surface of the cylinder. The available force can hardly, 
therefore, exceed two and a half pounds. The cross- section of the 
cylinder will, moreover, be not less than five and a half inches, and sub- 
stituting these numbers in the formula for velocity as before, we shall 
obtain as the velocity of the ascent five and a half feet. With this 
velocity the apparatus would reach the surface from a depth of five 
miles in one hour and twenty minutes, making the whole time of ascent 
and descent more than an hour and three quarters. By varying the 
number and dimensions of the buoys, the duration of the operation may 
be within certain limits varied, but it will always be great. The diameter 



612 PAEIS UNIYEESAL EXPOSITION. 

of the buoy cannot be indefinitely increased, since a point will soon be 
reached at which sufficient strength to resist the pressure can only be 
secured at a total sacrifice of buoyancy. 

The plan proposed by the inventors of the bathometer to secure con. 
stancy of temperature by surrounding the instrument with ice is one 
on which it would be hardly safe to place reliance. If the quantity of 
ice employed is considerable, its bulk will materially retard the velocity 
of descent, aud by protracting the time of exposure endanger its lique- 
faction. If it is small, liquefaction will be inevitable. The rapidity of 
liquefaction will, indeed, be very sensibly accelerated by the hydro- 
static pressure ; since it has been demonstrated by Mr. James Thompson 
that the freezing point is depressed, as pressure increases, by such a law, 
that, under a pressure of eight hundred atmospheres — that is to say. at 
a depth of five miles — the effect amounts to not less than six degrees 
Centigrade, or eleven degrees Fahrenheit. Still, it must be admitted 
that if it shall be found possible to maintain an ice bath surroirnding 
the instrument long enough to carry it safely through the depths at 
which in going and returning it is liable to be subjected to perturbations 
from varying temperature, an essential point will be gained. 

Turning now to the peculiarities of construction of the bathometer 
itself, it maybe questioned whether the form of pressure gauge proposed 
by them has any advantages over that of Perkins, recently revived 
with modifications by Johnson. The introduction of a second fluid, 
viz: mercury, which is itself to some extent compressible, while it 
increases the complication of the apparatus, adds a new element to the 
uncertainty of its indications. The admission of air for the purpose of 
increasing the sensitiveness of the indications is still more objection- 
able. The presence of two compressible bodies having co-efficients of 
elasticity so widely different as air and water in the same pressure 
gauge, would give rise to great inequalities in the scale : while the dis- 
turbing effect of temperature on air would be immensely greater than 
that which it produces in water. Moreover, if the instrument is to be 
made serviceable, the proportions of the liquids which it contains should 
never on any account be in the slightest degree altered. 

Supposing, however, that these difficulties should prove not to be 
insurmountable, it may be suggested that probably the dimensions given 
to the different parts of the instrument might be advantageously mod- 
ified. From the actual dimensions as given above, it may easily be 
computed that the index reading corresponding to an atmosphere of 
pressure will be only 0.00S inch. This is too small a difference to be 
read easily in a barometer, and must be still more difficult in an instru- 
ment unprovided with any zero correction for the varying level of the 
mercury in the reservoir. It is much to be desired that a simple and 
entirely trustworthy method of deep-sea sounding, free at the same 
time from practical difficulties, should be devised and brought into gen- 
eral use. The plan of Professor Trowbridge seems at present to be that 
which has most nearly resolved this important problem. 



CHAPTER XVIII. 
METROLOGY AND MECHANICAL CALCULATION. 

Measuring rules — Dividing instruments — Cathetometers — Spheromete rs — 
Comparators — Micro-pantographs — Froment's — Hardy's — Peters's — Planime- 
ters — Oppikoffer's — Amsler-Laffon's — Mechanical calculation — The Arabic 
numerals — counting machines — calculating machines — gerbert — albertus 
Magnus — Roger Bacon — Napier — His rods — Logarithms — Pascal's calculating 
machine — Leibnitz's — Gunter's logarithmic rules — Leblond's — Gattey's — Cal- 
culating MACHINE OF OPRANDINO MUSINA — Of THOMAS DE COLMAR — CAPABILI- 
TIES OF THIS MACHINE — BABBAGE'S DIFFERENCE ENGINE — SCHEUTZ'S— BABBAGE'S 
PROJECTED ANALYTIC ENGINE. 

I—MICROMETRY. 
Under this head may be classed not only instruments for the direct 
measurement of dimensions of length to the last extreme of accuracy, 
but also instruments for making the minute divisions of rules and cir- 
cles, for determining the curvatures of surfaces, and for reducing designs 
of sensible magnitude to microscopic dimensions. 

MEASURING RULES. 

Several admirable standard meter rales were exhibited by Dumoulin- 
Froment and by Deleuil, of Paris, and also by Breithaupt, of Cassel. 
That of the first exhibitor above named was divided to half millimeters 
on a silver surface, and read by a vernier to one two-hundredth milli- 
meter. Beautiful rules of wood, brass, and ivory were exhibited by 
many manufacturers, but especially by Elliott Brothers, of London. The 
admirably divided steel rules of Messrs. Darling, Brown & Sharpe, of 
Providence, Rhode Island, attracted also much attention. 

DIVIDING INSTRUMENTS. 

Dividing instruments were exhibited by Dumoulin-Proment and by 
Perreaux, of Paris, which, in respect to workmanship and precision, 
seemed to have exhausted the resources of art. The circular dividing 
machine of Mr. Perreaux consists essentially of a strong horizontal cir- 
cular plate, designed to carry the circle to be divided. This bedplate 
is toothed at its circumference and is driven by a tangent screw. The 
tangent screw is provided with a large circular head having a system of 
stops by which it may be arrested at a given fraction of a revolution, or 
allowed to make several revolutions before stopping. A horizontal 
metallic rod extends across the center of the circle, and to this the divid- 
ing apparatus is attached. This apparatus is movable on the rod, and 
may be fixed at any distance from the center, in order to accommodate 
circles of different diameters. Another adjustment permits it to be 
arranged so as to divide, if necessary, on a bevelled limb. The dividing 



614 PARIS UNIVERSAL EXPOSITION. 

tool is drawn back by hand, and returning performs its cut by the action 
of a spiral spring. As the lines marking the divisions are generally of 
the same length, but are periodically longer, as for instance at the fives 
and tens, the carriage of the tool is furnished with wheels having notches 
in the circumference, which, turning as the work advances, give, at the 
required intervals, the necessary increase of range. 

The machines for straight line division have a horizontal cast-iron bed 
on which the rule to be divided is fastened, and along which the carriage 
of the tool is driven by means of a screw resembling the screw of an 
engine-lathe. In Mr. Perreaux's machine the screw is of steel, and has 
a thread of half a millimeter. The head of this screw has divisions and 
stops resembling those of the machine above described for circle divid- 
ing; and the dividing tool is operated in a manner entirely similar. 

A small dividing instrument for ruling microscopic divisions was 
exhibited by Mr. Perreaux in an unfinished state. This machine has a 
screw of two decimeters (eight inches) in length, four millimeters iu diam- 
eter, and one-tenth of a millimeter thread. The head of the screw is a 
ratchet of ten centimeters in diameter, having 300 teeth. Each tooth 
advances therefore the ruling tool one three-thousandth of a millimeter. 
This corresponds to about 78,000 lines to the inch. It remains to be 
tested how far the expectation of the constructor will be realized. Mr. 
Robert, of Earth, Pomerania, has ruled microscopic bands with lines as 
close as 120,000 to the Paris inch, or more than 112,000 to the English 
inch. He has never made known the construction of the mechanism by 
which he does this ; and though his name was on the list of exhibitors 
from Prussia, he failed, to the great regret of all visitors acquainted with 
the results which his extraordinary skill has enabled him to achieve, to 
make his appearance. 

CATHE TOME TEES. 

Mr. Perreaux exhibited also a cathetometer, or instrument for vertical 
linear measurements, of the construction which he has already made so 
widely and so favorably known. This instrument consists of a tube of 
brass, turning on a vertical steel axis which it incloses, and which is 
fixed in a solid tribrach of iron furnished with leveling screws and 
levels. The tube is provided on two opposite sides with vertical ribs or 
guides, along which a carriage slides up and down, carrying a telescope 
with delicate level attached, and also, sometimes, a dividing tool. The 
carriage may be clamped at any altitude, and when clamped, may be 
moved slowly by means of a micrometric screw. The tube is graduated 
and the carriage has a vernier, by means of which the reading may be 
carried to the two-hundredth part of a millimeter. 

SPHEK OVLETEES. 

Mr. Perreaux also exhibited a spherometer, or instrument for measur- 
ing the curvature of surfaces. It may also be employed for determining 
the thicknesses of very thin plates of any solid substance. The original 



METROLOGY AND MECHANICAL CALCULATION. 615 

spherometer consisted of a three-armed frame standing- on three vertical 
steel pins forming with each other an equilateral triangle. In the cen- 
ter of the instrument a vertical screw with fine thread, having a large 
divided head, is turned downward until the point reaches the surface on 
which the instrument stands. If this surface is truly plane, the gradua- 
tion should be such that the index under these circumstances will mark 
zero. On placing the instrument upon a spherical surface, whether con- 
vex or concave, and again making contact, the corresponding positive or 
negative reading will indicate the degree of sphericity. This construc- 
tion renders the use of the instrument somewhat difficult, and leads to 
some uncertainty as to the results of observations. In Mr. Perreaux's 
spherometer the central screw is perforated longitudinally throughout its 
axis; and through the perforation thus formed passes a slender rod of 
steel held in position only by slight friction. The top of this rod expands 
into a knife edge, and across it lies, above the screw, a lever which is 
attached at one end very near to the knife edge, to a stud in the screw- 
head, by a joint. It is evident that if the screw goes up or down car- 
rying the rod with it, the horizontality of the lever will be undisturbed. 
But if the screw goes down while the rod stops, the free end of the lever 
must rise. This is what must happen when, in the use of the instru- 
ment, contact is made with the surface under examination. The moment 
of contact is thus detected with great accuracy. In order to increase 
the sensitiveness of the instrument, Mr. Perreaux has introduced a sec- 
ond lever which is acted on by the first. The extreme delicacy of the 
determinations of which it is thus made capable is truly surprising. 

A spherometer of great ingenuity and delicacy was also exhibited by 
Mr. Julian Giordano, of Naples, in the Italian section, in which the con- 
tact of the central screw was determined by the passage of a galvanic 
current giving an alarm. It was called by him the electric spherometer. 

COMPARATORS. 

Comparators are instruments for ascertaining the agreement or disa- 
greement of two measures having nominally the same length. In appear- 
ance they present some resemblance to the machines for dividing right 
lines. A horizontal bed of cast iron is provided to receive the rules to be 
compared. These rules may be constructed so as to include the required 
length between their extreme terminal surfaces, in which case they are 
then called measures a bout; or they may be so formed that the length 
shall be limited by lines traced upon the lateral surface of the rules, and 
they are then called measures a trait. Measures a bout are placed between 
the short arms of two " contact levers," the long arms carrying verniers 
which traverse nicely divided arcs and which are read by microscopes. 
The support of one of these levers is firmly fixed to the base of the 
machine; that of the other is attached to a sliding carriage by means 
of which it may be placed at the suitable distance from the first and 
clamped. This support is also commanded by a micrometric slow move- 



616 PARIS UNIVERSAL EXPOSITION. 

ment produced by a longitudinal screw of fine thread having a large divided 
circular head. The rule being in position, the vernier of the fixed lever 
is first brought to zero. This is accomplished by a slow movement of 
the rule itself with the bed on which it rests. The vernier of the mova- 
ble lever is afterwards brought to zero by moving the support of the 
lever through the instrumentality of the micrometric screw above men- 
tioned. The length of the rule is then given by reading, for the larger 
divisions, a longitudinal scale which the sliding support of the lever 
traverses; and for the fractional subdivisions, the dial of the screw 
head. In general, when a rule is to be compared with a standard of the 
same nominal length, the larger divisions may be neglected as being the 
same for both, and the dial of the screw head only read. In this case 
the two rules must of course be examined successively ; and the differ- 
ence of the readings of the dial will be the difference of their lengths. 
The value of one division of the dial in Mr. Perreaux's comparator for 
meters or longer bars is one four-hundredth of a millimeter. Mr. Silber- 
mann's comparator at the Conservatoire des Arts et Metiers reads to one 
one-thousandth of a millimeter. In determining differences so minute, it 
is indispensable to take into account the temperature of the instrument 
and that of the rule at the time of observation, and to reduce the observed 
length to what it should be at a standard temperature, by allowing for 
the effects of expansion or contraction. Even the results obtained by 
such reductions are not always satisfactory; since it is rare to find two 
bars of the same metal to which the same coefficient of expansion will 
severely apply. The mode of observation most certainly to be relied on 
is that in which the whole instrument, including the rule, is immersed 
completely in a bath of melting ice. 

It sometimes happens that the terminal surfaces of a bar are not 
exactly parallel. In this case a measure a bout will give different 
results according as the contact levers are applied in the middle or near 
the sides. Mr. Perreaux's comparator is provided with the means of 
testing the accuracy of this parallelism. The whole bar may be moved 
laterally by means of two entirely similar screws, one near each end. 
which turn with the same angular motion. In this slow progress, if the 
verniers of the two levers indicate no change of reading, the surfaces 
are inferred to be parallel. If one or both the readings change, the 
amount of change will indicate the amount of inaccuracy. 

When the reading is a trait the contact levers are unnecessary. For 
the examination of bars of this description two microscopes are employed, 
placed vertically over the bar upon the bed of the comparator, each being 
provided with a micrometric eye-piece. The manner of making com- 
parisons in this case requires no particular description. 

For the comparison of the subdivisions of a scale throughout its 
length, with the view of testing their uniformity, two microscopes are 
fixed to a common sliding base and are brought to include between them 
any determinate number of divisions. By the movement of the com- 



METROLOGY AND MECHANICAL CALCULATION. 617 

mon base from end to end, it will easily be determined whether the same 
number of divisions on the scale corresponds everywhere to the same 
absolute space, and if not, what and how great are the irregularities. 
For the purpose of varying the test, the distance between the two micro- 
scopes upon their common base admits in the comparator of Mr. Per- 
reaux of being increased or diminished to any extent between the limits 
of five centimeters and twenty centimeters. 

A similar comparison may be made between the divisions of two 
scales, which are both of them at the same time on the bed of the com- 
parator. In order to effect this one of the two microscopes must be 
advanced beyond the other, in a direction at right angles to the length 
of the scale, to such a distance that while one of them reads the standard 
the other reads the scale to be tested. In such a comparison it is well 
to place the microscopes as near together as possible, and having brought 
one of them truly over the first division of the standard, to move the 
scale under scrutiny longitudinally until its first division comes truly 
under the other. Then, as the microscopes are both advanced by the 
movement of their common base, the readings of the two ought to be 
constantly the same, and the differences of reading will indicate the 
amount of disagreement. If the standard is known to be absolutely 
correct these disagreements will be the errors of the rule under examina- 
tion. If the standard has errors, these, of course, ought to be known, 
and the errors of the rule on trial will be deduced by a proper combina- 
tion of these with the observed discrepancies. 

In the exposition of Mr. Dumoulin-Froment there was exhibited a 
new form of comparator constructed according to the designs of Mr. 
Tresca, of the Conservatoire des Arts et Metiers, which promises consid- 
erably to expedite comparisons. In this but one microscope is used, 
and both rules to be compared are placed side by side upon the bed. 
The whole bed of the instrument is movable upon nicely-constructed 
ways, both longitudinally and laterally. One end of the standard is 
first brought truly under the microscope, and then, by the lateral move- 
ment, the scale on trial is brought in turn into the field of vision, and 
subsequently, by the slow movement of this scale itself, if necessary, 
its mark of verification is brought to the cross-lines of the instrument. 
These adjustments having then been verified, the whole system is moved 
longitudinally until the opposite ends of the bars come under observa- 
tion. Without disturbing the microscope the mark on the standard is 
first brought to the cross-lines, and subsequently, by the lateral move- 
ment again, the other bar is brought into view, when the differences of 
length, if any, may be measured by the micrometer. This is a great 
simplification upon the comparators heretofore in use. Its performance 
in practice will be looked for with interest. 

MICRO-PANTOGRAPHS. 

Of micro-pantographic instruments there was but one exhibited, which 
was in the exposition of Mr. E. Hardy, of Paris. The first micro-pan- 



618 PARIS UNIVERSAL EXPOSITION. 

tograph for engraving on glass ever constructed is believed to have been 
that of the celebrated Froinent, whose son-in-law, Mr. Dumoulin-Froment, 
still honorably maintains the high reputation so long enjoyed by him. 
In principle, this instrument is extremely simple. The wonderful part 
of it is the almost miraculous accuracy of workmanship which preserves 
in movements inconceivably small a severe accuracy of proportions not 
easily secured in instrumental drawings even of considerable dimensions. 
The essential part of the instrument is a vertically-suspended lever, 
pivoted near the upper extremity in a universal joint. If this lever 
moves in its pivots the two extremities describe similar figures, but these 
figures are unequal in dimensions in the same proportion as the lever 
arms are unequal. And accordingly, if the lower extremity be made 
to trace out the characters of an inscription or the lines of a drawing, 
the upper extremity will perform all the motions necessary to pro- 
duce a similar drawing or inscription reduced, and of which the scale 
of reduction will depend upon the relative lengths of the arms. In the 
ordinary pantographs the lever which produces the drawing carries a 
pencil which moves with it. In the micro-pantograph it is the glass 
receiving the drawing or inscription which moves, while the tracer which 
cuts the lines, and which is a fragment of diamond brought to an exceed- 
ingly fine point, remains motionless. 

With a single lever it is possible to make a reduction in the ratio of 
one or two hundred to one. But by employing a second lever to act 
upon the first a larger reduction may be secured, of which the ratio will 
be found by compounding the ratios of the two successive reductions. 
The instrument exhibited by Mr. Hardy appeared to have but one lever. 
In the Exposition of 1862, however, there was exhibited an instrument 
of similar description, in which, by a combination of two levers, the 
reduction was carried to the extraordinary extent of six thousand two 
hiiDclred and fifty diameters. In this machine, invented and constructed 
by Mr. W. Peters, of London, the levers were so contrived as to allow 
the scale of reduction to be varied at pleasure, from the extreme limit 
just mentioned down to one hundred and ten diameters, according to 
the character of the work to be done. The following extract from the 
account of this instrument, given by Dr. Brooke, in the jury report on 
the instruments of precision exhibited in that Exposition, will be read 
with interest as illustrating its almost miraculous powers : 

"The lower end of the lower lever carries a pencil or tracer connected 
with it by two equal and parallel links, which is passed by the operator's 
hand over the desigu or writing to be copied. The upper end of the 
upper lever carries the piece of glass for the reception of the diminished 
copy. Over the glass is mounted a diamond, pointing downwards, which 
remains stationary while the glass moves under it. the usual process of 
writing being here reversed. Mechanism is connected with the diamond, 
by means of which it can be raised or lowered, and also pressed with 
greater or less force upon the glass ; and so efficient are these contriv- 



PETERS 7 S MICRO-PANTOGRAPH. G19 

ances that the thick and thin strokes of ordinary writing can be faith- 
fully transferred to the minute copy on glass. 

U A full and lucid description of this most interesting machine, of which 
the above is but an outline, is published in the transactions of the micro- 
scopic society in the form of a paper by its president, K. J. Farrants, esq., 
read 25th April, 1855 ; and some further particulars are given in the 
president's address to the same society, delivered 12th February, 1862. 

"The following statements of its powers which, on inferior authority 
would hardly be credited, are given by Mr. Farrants: 

"'The name and address of Mr. Mathew Marshall, Bank of England, 
have been written in 2T00W0 °^ an mca ? the two and a half millionth part 
of an inch. The Lord's Prayer, too, has been written, and is legible, in 
the 3 3^00 °f an English square inch. The measurements of one of the 
specimens were verified by Dr. Bowerbank, with a difference of not more 
than one five-millionth of an inch, and that difference, small as it is 
arose from his not including the prolongation of the letter/ in the sen- 
tence u deliver us from evil j" so he made the area occupied by the writ- 
ing less than that stated above. Some idea of the minuteness of the 
characters in these specimens may be obtained from the statement that 
the whole Bible and Testament in writing of the same size might be 
placed twenty -two times on the surface of a square inch. The grounds 
for this startling assertion are as follows : The Bible and Testament 
together in the English language, are said to contain 3,566,480 letters. 
The number of letters in the Lord's Prayer, as written, ending in the 

sentence u deliver us from evil," is 223, whence as 3,5 ^l 48 - = 15,922, it 

appears that the Bible and Testament together contain the same num- 
ber of letters as the Lord's Prayer written 16,000 times ; if, then, the 
prayer were written in T ^oo of an iuca ? tlie Bible and Testament in 
writing of the same size would be contained by one square inch ; but as 
3W0 °f au i nca i s one twenty-secondth part of T -^ \^ of an inch, it 
follows that the Bible and Testament in writing of that size would occupy 
less space than one twenty-seventh of a square inch.' 

u It only now remains to be seen that, minute as are the letters writ- 
ten by this machine, they are characterized by a clearness and precision 
of form 'which proves that the moving parts of the machine, while pos- 
sessing the utmost delicacy of freedom, are absolutely destitute of shake, 
a union of requisites very difficult of fulfillment, but quite indispensable 
to the satisfactory performance of the apparatus." 

More interesting, perhaps, than the excessively minute inscriptions 
above mentioned, if not to the same degree marvelous, are the micro- 
scopic copies of drawings and designs executed by the same ingenious 
mechanism. These are reduced from any subjects which may be proposed 
with remarkable expedition and with admirable fidelity. There is in 
the possession of the writer a copy of the device borne by the seal of 
Columbia College, Xew York, executed for him by Mr. Dumoulin-Fro- 



620 PARIS UNIVERSAL EXPOSITION. 

ment, within a circle less than three one-hundredths of an inch in diame- 
ter, in which are embraced four human figures aud various other objects, 
together with inscriptions in Latin, Greek, and Hebrew, all clearly legi- 
ble. In this device the rising sun is represented in the horizon, the 
diameter of the disk being about one three-thousandth of an inch. This 
disk had been cross-hatched by the draughtsman in the original design 
from which the copy was made ; and the copy shows the marks of the 
cross-hatching with perfect distinctness. When this beautiful and deli- 
cate drawing is brought clearly out by a suitably adjusted illumination, 
the lines appear as if traced by a smooth point in a surface of opaque 
ice. 

II.— PLAOTMETKY. 

An expeditious mode of ascertaining the area of irregular plane fig- 
ures is for many purposes of great utility. Apart from the obvious 
advantages of such a method as applied to the measurement of plots of 
ground in surveying, its uses to the mechanical engineer in determining 
the amount of work performed by a machine by means of dynamometri- 
cal curves, and the tracings of the indicators attached to steam cylin- 
ders, in which the contours of the figures to be measured are irregularly 
variable, is very great. A planimeter was invented more than thirty 
years ago by Oppikoffer, of Berne, which in theory seemed to fulfill 
every desirable requisition, and which was reccommended to its employes 
by the administration of the public surveys in France. Its expensive- 
ness and the practical difficulties found to attend its use prevented its 
general adoption ; but it continues still to be to some extent employed 
by mechanical engineers. A simpler instrument, and one much less 
costly, was exhibited in the Swiss section of the Exposition, by Mr. 
Amsler-Laffon, of Sckaffhouse. The theory of this instrument will be 
better understood after a brief explanation of the planimeter of Oppi- 
koffer. 

oppikoffer's plantmeter. 

In the annexed figures, of which the first is a plan and the second a 
lateral view, are embraced the essential parts of this instrument. These 
are, first, a cone G, mounted on a movable carriage. M X. with the axis 
inclined in such a manner as to bring one side into a horizontal position. 
A rod X Y, parallel to this side of the cone, slides in the direction of its 
length through supports A B attached to the carriage. This rod is rect- 
angular, or otherwise formed so as to be incapable of turning on its 
axis. At one extremity it carries a poiut, or tracer. P. which, in the 
use of the instrument, is employed to follow the perimeter of the figure 
the contents of which it may be desired to ascertain. Upon the rod is 
fixed a small wheel or roller ^Vv", convex upon its circumference, which 
turns freely upon the rod by frictional contact with the cone C. The 
axis of the cone, between its base and the bearing, carries a small pulley. 



METROLOGY AND MECHANICAL CALCULATION. 



G21 



around which passes a stretched cord, c, extending from end to end of 
the framework, or railway, E E, upon which the carriage traverses. 
By the movement of the carriage the cone is thus made to revolve, and 

Fig. 142. 




Vertical view. 



Fig. 143. 







Oppikoffer's Planimeter — end view. 

its motion of revolution is transferred to the wheel W. A rack and 
pinion might evidently be substituted for this cord. In the machine as 
complete there is a mechanical register connected with the small wheel 
W, and with the sliding-rod, which records the revolutions made by the 
wheel when the instrument is in use. The construction is therefore con- 
siderably less simple than it is here represented. The carriage runs on 
rollers on the ways E E, as it is moved by the hand of the operator. 

It is obvious that, for the same movement of the carriage, the rapidity 
of revolution of the wheel W will be variable, according as it is nearer 



622 PARIS UNIVERSAL EXPOSITION. 

the summit or the base of the cone. If the sliding-rod be pushed in the 
direction A B, until the wheel W reaches the vertex of the cone, the 
wheel will cease to revolve altogether, although the movement of the car 
may still be continued. Supposing it to be in this position, and the 
point P consequently at O, the tracer may pass along the line X Y, 
through the whole range of the instrument, without making any record. 
By sliding the rod in the opposite direction so as to bring the tracer to 
the line W Z, and the wheel to the base of the cone, the roller in the 
course of its movement from W to Z, will make its largest possible 
record. During this progress the rod will sweep over all the area W X 
Y Z $ and if this area be supposed to contain a certain number of square 
inches, two hundred for example, and the count of the register should be 
so adjusted as to read two hundred units at the end of the movement, 
(the original reading having been zero,) it will be seen that the record 
will truly exhibit the area passed over. Of course, if the movement had 
been arrested half-way between W and Z, the record would have been 
but one hundred, and the area passed over only one-half of that before 
supposed. Again, if returning to the line W X, and seeing that the index 
is once more truly at zero, the tracer is moved along the line WX, half-way 
to X, this motion will cause no change in the position of the roller, because it 
takes place perpendicularly to its plane, but the roller will be trao sferred to a 
point on the cone half-way between the base and the apex, where the 
circumference is only half what it is at the base. In making then anew 
the movement from the line W X to the line Y Z, the roller will make 
but half as many revolutions as before, and the register will record but 
one hundred units. In the mean time, also, the rod will have swept over 
only half the area of the rectangle AY X Y Z. What is true of these 
particular cases will obviously be true of every case. In moving in the 
direction from W X toward Y Z, the register will always truly record 
the amount of surface swept over. Suppose the irregular but rectilinear 
and rectangular figure ah c clef i Jc / m n o to be placed before the instru- 
ment for measurement in the position represented. Let the tracer be at 
a and the index at zero. In carrying the point P along the line a b. the 
area a b p X is swept over, and its value recorded. If then the tracer 
be carried along the line b c, no record will be made, because the move- 
ment is at right angles to the plane of the roller. In this movement, 
moreover, no new area is swept over. In moving from c to tf, the addi- 
tional rectangle c d a p is covered by the rod, and a corresponding 
addition is made to the record. From d to e there is no area and no 
record. From e to/, the area efsqis described, and its amount is added 
to the previous sum. We shall thus have measured the whole area, 
ab c d ef s X. Passing now to </, which will not change the reading of 
the register, we return from g to h. The rod passes over the area g h r s : 
but as this movement is in a contrary direction to the former, the roller 
turns backward, and thus subtracts from the total previously obtained 
the value of this small rectangle. We proceed then from li to i without 



METROLOGY AND MECHANICAL CALCULATION. G23 

a record, and from i to lc subtracting the rectangle ilc q r. In like man- 
ner we subtract I m p q and n o X p, and finally return along the line o a 
to the starting point, with a final reading of the register which is equal 
to a b c d ef s X, diminished by ghiTclmnolLs) or to the given figure 
abed efg h i Jc I m n o. 

Take next the rectilinear figure G- H K L, of which the sides are not 
parallel to those of the rectangle W X Y Z. We may describe upon it 
a series of rectangles as shown, of which the sides shall be so parallel ; 
and these may be so described that their salient angles may touch the 
sides of the figure internally, or so that the re-entering angles of the 
group may meet the same lines externally. The differences of the first 
set of these small rectangles, measured as above, will be less than the 
area of the figure, and those of the second set greater ; but the excesses 
or deficiencies will be so much the less considerable as the rectangles 
are made more numerous, and are severally smaller, while the instru- 
ment will measure every system with equal accuracy, whatever be the 
dimensions of its elementary parts. Supposing the breadth of these 
rectangles to be infinitely diminished, their angles disappear, and the 
tracer, in measuring them, follows the sides of the given figure G H 
K L. Such is the theory of this very ingenious instrument. In the 
actual construction, the circumference of the base of the cone is made 
equal to the generating line of the convex surface. Accordingly, when 
the wheel W is one inch from the vertex, it makes one complete revolu- 
tion for every inch which the tracer P moves in the direction X Y. But 
this is not an essential condition. If a square inch is the assumed unit 
of surface, all that is necessary to the correctness of the record is, that 
when the tracer K is one inch advanced beyond the line X Y, as for 
instance at O, the register shall record one unit for every inch of move- 
ment in the direction from X toward Y. 

i 

amsler's planimeter. 

From what precedes, the theory of the planimeter of Amsler will be 
easily intelligible. The instrument is shown in perspective in Fig. 144. 
The arm A slides in the socket H, and may be adjusted to such length 
as best suits the work in hand. It carries on the side or top certain 
marks or graduations, with numbers annexed, expressive of the value of 
certain constants, to be used as will presently be described, in deducing 
the final results. Each length given to the arm A requires a different 
constant. The socket H has beneath it the apparatus for registration, 
which consists, first, of a roller, graduated on its circumference, and 
provided in the prolongation of its axis with a screw-thread, which acts 
upon the small horizontal graduated disk G, by means of a pinion. The 
entire revolutions of the roller are recorded by this disk ; an index on 
the left serving to mark the divisions as they pass. The reading of 
fractional parts of a revolution is made by means of a vernier, shown at 
L. A horizontal rod B is hinged to the apparatus just described, and 



624 



PARIS UNIVERSAL EXPOSITION. 



is fixed to the table, when the instrument is in use, by means of a point, 
E, at its extremity. At F is a tracer, which, as in Oppikoffer's plan- 
Fig. 144. 




Amsler's Planimeter. 

imeter, is carried along the lines of the figure to be measured. The 
instrument rests, therefore, on the roller D, and the revolution of this 
roller is produced by friction upon the paper. The point E being fixed, 
and all other parts of the instrument free, the movement is necessarily 
circular; and on this account the instrument is sometimes called the 
polar planimeter. If we suppose the joint connecting the two rods at 
C to be inflexible, and the tracer F to be carried round E as a center, it 
will be perceived that the moving point will describe a circular arc, of 
which the line joining E F is the radius. This moving radius E F will 
sweep over a sector, of which the arc is the base, and the radii in the 
initial and final positions the lateral boundaries. In the mean time the 
roller D will turn by friction on the paper, and the geometrical fact upon 
which the usefulness of the instrument depends, is that the extent of 
the arc developed by the roller is a simple function of the area of the 
sector swept over. 

c 





a c 

Fig. 145. Fig. 146. 

The theory of this instrument therefore supposes that every plane 
figure submitted to measurement is made up of infinitely small eircu- 



THEORY OF THE AMSLER PLANIMETER. 



625 



W 



-4 



/ 



M. — .J, 



X 



lar sectors, or of the differences of such sectors, precisely as Oppi- 
koffer's planirneter supposes the resolution of the same surfaces into 
minute rectangles. In Fig. 145, on page 624, if we can measure the 
whole sector A E, in sweeping directly from A to 
E, and then, returning along E E', E' D', D' D", 
D" C, C C", C" B", B" B', B' A', and so to A 
again, can measure the several sectors E' D', 
T>" C, C C" B", and C B' A', these areas being sub- 
tracted from the former by the instrument itself in ^ 
the contrary movement, there will evidently remain 
the irregular area AEE'D' D" / C" B" B' A'. 
Fig. 146 shows the extension of the principle to rec- 
tilinear figures, and this may be compared with 
Fig. 142 of Oppikoffer's planirneter. 

It is evident that, in the various movements of ^ 
the instrument, the roller must, at different times, 
be differently inclined to the direction in which it is 
drawn along over the paper. In passing over a 
given length of track, it will not therefore always 
develop the same length of arc. It is upon this fact 
that the truthfulness of the indications depends. 
Fig. 147 illustrates the relation which subsists be- 
tween the space passed over and the arc developed. 
If a roller be moved on a plane surface from A to B 
to its plane, it will slide 
without turning. If it 
be then carried forward 
in the direction of its 
plane from B to C, being 
free to roll, it will de- 
velop an arc equal to B 
C. And if it be carried 
in a straight line, A 0, 
from the initial to the 
final point of movement, 
it will both slide and 
roll, and the arc devel- 
oped will still be B 0. 
The direction of the 
plane of the wheel being 
A A', and that of the 
path being A 0, the 
angular inclination be- 
tween the two will be 
A'AO; and if this an- 
40 I A 



Fig. 147. 

at right angles 




626 PARIS UNIVERSAL EXPOSITION. 

gle be represented by ?, the length of path by #, and the arc developed 
by 0, the relation expressed in the following equation will always sub- 
sist, viz : 

0=acos (p. 
In order to apply this principle to the operation of the planimeter, we 
refer to Fig. 148, in which P represents the fixed pole; Q the roller; E 
the point of union of the arms ; and S the tracer. Supposing the joint 
to be inflexible, and the instrument to revolve about P, the tracer will 
describe the arc MN, and the roller the arc WIS'. Simultaneously the 
two small sectors, PST and PQT', may be supposed to be swept over by 
the radii, PS, PQ. Put to represent the arc developed by the roller ; 
6' the arc QT' actually moved over ; and 0" the arc ST described by the 
tracer. Put also <p = the angle of the plane of the roller to the tangent 
Qc, that is, to &Qc=PQa; and V=the angle PRQ. Then, as above — 

a 

0=0' COS a>; or 0'= . n . 

cos (1.) 

If now we put PR= a; ES=&; BQ=c; PS=/>; andPQ=r; and take 
S to represent the area of the sector PST, we shall have 



S=£/>0": 6"= p -d r . ' S= p -J-. 

And finally (1.) S=-^_ . (S> i 

v 2r cos tp (2.) 

In the triangle PSE, 

p 2 =a 2 +b 2 +2abcosi>. 
But it is evident from the figure that 

acos V , =r cos f+c. 
Whence p 2 =a z +W+2bc+2br cos <p. 
And substituting in (2.) 

g _ (a 2 +& 2 +2&c+2&r cos <f) _ (a 2 +b 2 +2bc) 6 ^ 
2r cos <p 2r cos <p 

In the first term of this value, substitute the value of 0=0' cos cr, and 
there results — 

S=%(a 2 +b 2 +2bc)- + b0. 

0' 
But — , or the arc divided by its radius, is the angular movement, or 

the similar arc corresponding to radius=l; which, if we put=«j we 
shall have finally, for the value of the sector, 

S = %(a 2 + b 2 + 2bc)w + b0. 

The angle oj is independent of the position of the roller, and its co- 
efficient is made up of constants; whence the area of the sector PST is 
measured by the product of the length of the arm ES into the arc 
developed by the roller, together with a constant multiplied into the 
angular measure of the sector. 



THEORY OF THE AMSLER PLANIMETER. 



627 



The constant in the above expression will be seen to be equal to the 
value which belongs to PS in the position represented in Fig. 149, where 
Q is a right angle. Eepresent this radius by R, and we shall see that 
£R«> expresses the area of a sector in a circle W'X'Y'Z', of which the 
constant radius is determined by the condition that the plane of the 
wheel shall be at right angles to the circumference of the circle WXYZ, 
which is the direction of its movement. While the wheel is in this posi- 
tion it slides without revolving. Hence, for the entire circle W'X'Y'Z' 
no record will be made ; and if, in the measurement, the tracer is carried 
entirely round the pole P, it is necessary to add a constant which is 
equal to this circle in value. 

If the figure measured lies wholly on one side of the instrument, as in 
Fig. 144, the constant occurs in the subtractive part of the movement as 
well as in the additive ; and hence no account need be taken of it. 




Fig. 149. 

The term bo, which is the variable part of the value of S, measures the 
portion of the sector PST, Fig. 148, which is between the arc described 
by the tracer and the circumference of the constant circle only. Taking 
in Fig. 149, PS' equal to PR + RS, and sweeping with the tracer around 
an entire circumference, 1)0 ought therefore to be equal to the ring con- 
tained between the two circumferences W'X'Y'Z' and W"X"Y"Z". 
This ring equals 

7r(PS /2 -PS 2 )=^((a + &) 2 -((l 2 + & 2 + 2&c)^==7r(2(a-c)?>Y 



628 PARIS UNIVERSAL EXPOSITION. 

In the position supposed, PR and ES being in a straight line, the 
plane of the roller coincides with the plane of its motion, cp=0°, cos p=l, 
and 6=0'. 

Hence, in the entire revolution, Q' taking the place of Q, 

&0=&(circumf.^ 

Which being equal to the area of the ring as just found, confirms the 
conclusion above deduced. 

When a figure lies entirely within the ring just mentioned, as ABODE, 
the additive part of the record is made while moving along the outer 
lines from E to A, from A to B, and from B to : the subtractive part 
while returning from C to D and from D to E. 1 But if we suppose this fig- 
ure enlarged so that its sides BC, AE, cross the circumference W'X'Y'Z', 
the roller which is turning in the positive direction while the tracer 
moves along BC, ceases momentarily at Y to revolve, and then from Y 
to C turns in the contrary, or negative direction. But it is now mea- 
suring the space YC'X' which is external to the figure, lying between it 
and the fixed circle W'X' Y'Z', and Avhich ought to be subtracted • while 
in the subsequent movement from C to Y' the entire space C'X'YY' is 
added to the positive record, and the difference of the two is the part 
YV'C of the figure. Thus the areas expressed by 1)0 are always referred 
to the circumference of the fixed circle W'X'Y'Z 7 as a base, whether 
the line described by the tracer is within or without this circle. 

From this consideration it results that when the pole of the instru- 
ment is in the interior of the figure, as at P, Fig. 149, and the sides of 
the figure are wholly exterior to the circumference of the fixed circle 
W'X'Y'Z', the record of the register is the sum total of all that part of 
the figure which is between the said circumference and the perimeter, 
and is Wholly positive. But when any part of the perimeter lies within 
the fixed circle, so much of the record is negative as relates to the spaces 
between such portions of the perimeter and the circumference. If the 
negative areas exceed the positive, the final record will be negative. It 
is therefore best to set the register at the number denoting the value of 
the constant circle before beginning the measurement ; since, so long as 
the figure has any magnitude, the negative areas cannot exhaust this 
entire constant. In Fig. 149, ABG'H'K'L'aP is an area in which this expe- 
dient would evidently be necessary in order to secure a positive result. 
But there are often cases in which it may be doubtful what would be 
the sign of the result without the addition j hence it is better always to 
make it. 2 

1 As the instrument is ordinarily graduated, the record diminishes in moving- from right 
to left. With such a graduation it is necessary to pass over the sides of the plot in an order 
the reverse of that stated in the text ; i. e., from E through D, C, B, and A to E again. 

2 The demonstration of the theory of the Amsler planimeter given in the text is the same 
in principle, though not in form, with that given by Messrs. Piecard and Cueuoud. The 
result may be reached more briefly by finding directly an expression for the area of the ring 



AMSLER'S PLANIMETER MECHANICAL CALCULATION. C29 

In the construction of the instrument it is desirable to proportion its 
several parts in such a manner that the rectangle of the arm b into the 
entire circumference of the roller may be some convenient unit of surface, 
or a definite number of such units. The number of revolutions, or of 
revolutions and fractions, recorded by the register, will then be either 
directly the expression of the area sought, or easily convertible into such 
an expression. For different lengths of the arm the values will be pro- 
portioned to the length. Hence it is easy to make them such as to facil- 
itate calculation, 1, 2, 5, 10, for instance. For each length of the arm b 
a new value must be computed for the constant circle, and this will not 
necessarily be a round number ; but as it is merely additive, its form is 
unimportant. 

This planirneter from its simplicity and its cheapness seems to be 
destined to come into more extensive use than that of Oppikoffer. Its 
price is only from 50 to 80 francs ; while that of the instrument of Oppi- 
kolfer is from five to six hundred. There is a possibility of error in its 
indications, as there must always be in instruments in which friction is 
relied on for the transmission of motion ; but it is so easy to make 
repeated measurements, and each measurement requires so little time, 
that no serious error is likely to vitiate the ultimate determination. 

III.— MECHANICAL CALCULATION. 

At first thought nothing seems more paradoxical than to propose to 
perforin operations in arithmetic by machinery. To most persons the 
process of calculation involves a species of mental labor which is painful 
and irksome in the highest degree ; and to such, no part of their educa- 
tional experience recalls recollections of severer trials, or of burdens 
more difficult to bear. That this toil of the pure intelligence — for such 
it certainly seems to be — can possibly be performed by an unconscious 
machine, is a proposition which is received with incredulity ; and even 
when visibly demonstrated to be true, is a phenomenon which is witnessed 
with unmingled astonishment. And yet all of us have been more or 
less in the habit of employing artificial helps to calculation all our lives. 
The same thing has been done by all races of men, and in all ages, even 
before the dawn of civilization. 

lying between the circumference of the circle, calied above the ji.ced circle, aud that corre- 
sponding to any value of the variable radius p. Putting A for the area of this annulus, and 
employing the notation given above, we shall have — 

A = 7T(p 2 — R*) 

And as we have found p 2 = a 2 -f- b 2 -f- 26c -f- 2br cos 0, 
And R 2 = « 2 + 6 2 -f-26c, 
It follows that A = 27rbr cos $ 
Now 2rrr is the circumference traced at the same time by Q, the roller ; and if 6 represent 
the arc developed by the roller in the same time, it follows (pp. 625, 628, Fig. 147,) that — 

6 = 2irr cos <p. 
Hence A = bd, as above. This proposition, though here applied to the case of an entire 
revolution, is equally applicable to any arc w, less than ir. 



630 PARIS UNIVERSAL EXPOSITION. 

The word calculation itself recalls the calculi,' the pebbles, which, next 
to the fingers of the human hand, formed the earliest, as they were the 
simplest, of all calculating machines. Nor should we forget that, 
laborious as are numerical operations generally, and intolerably weari- 
some as we find them when they are greatly protracted, they are the 
mere sport of children compared with what they would have been with- 
out the aid of an artificial system of numeration, like that which is pro- 
vided in the Arabic numeral characters. Our system of numeration, if 
not a machine, is a machinery ; and without it, or without something 
substantially equivalent to it, every numerical problem involving more 
than a very limited number of units would be totally beyond the grasp 
of the human mind. 

Machines for simply counting are common and familiar. We see them 
constantly in use for numbering railroad tickets, bank-notes, and other 
similar objects, and they are attached to steam-engines to record the 
number of revolutions made during a day or during a vogage ; or to 
gas-meters to keep account of the volume that has been consumed during 
a determinate time. None of these things excite surprise. There is no 
mystery in the fact that a machine can be made to count, though in the 
case of the class of instruments last named it sometimes appears to 
customers very mysterious that they can be made to count so much. 

But in the counting machine is involved the essential principle of all 
machines for calculation. It is obvious that the machine which will 
count single units may be be made to count tiros, threes, tens, fifties, 
just as well. The necessary modifications are matters only of mechanical 
detail. But this process is multiplication ; so that, except for the increased 
number of parts, a multiplying machine is only a counting machine in a 
new form. Division is multiplication reversed; and when the direct 
process is possible the reverse follows as matter of course. 

The ordinary counting machine adds at each operation a single unit 
to the previously accumulated sum. A multiplying machine, such as we 
have just supposed, may add to the preceding sum the whole of a given 
multiplicand, though consisting of many units, at every successive move- 
ment. But in order to adapt such a machine to the varying uses of the 
arithmetician the construction must be such as to allow the operator to 
alter the multiplicand at his pleasure. Granting that this end has been 
secured, then any product of any two numbers may be obtained with no 
further trouble on the part of the person using the machine than that of 
setting and turning it. Or if we suppose the machine to be driven by a 
mechanical motor, then the only attention which it will be necessary to 
give to it will be, first, to set the markers of the scale to the multiplicand, 
and secondly, to place a stop for the purpose of arresting the movement 
when the multiplier has been exhausted. When the machine stops the 
product will appear. 

Machine addition is more troublesome than machine multiplication, 
because it requires the attendant to re-set the markers after each sue- 



CALCULATING MACHINES. 631 

cessive movement. There seems to be no getting over this difficulty, 
and no reducing of simplicity lower. Though the machine will fulfill 
perfectly the function of a mechanical memory, the mind must dictate 
in the first instance what it is to remember. 

Subtraction being only the reverse of addition, it is provided for 
when addition is made possible ; and thus it is seen how, without invok- 
ing any other principle, mental or mechanical, than is already familiar 
to all the world, it is quite possible to construct a machine to perform 
all the operations of ordinary arithmetic. 

And yet, while in the theory of the calculating machine there is noth- 
ing which is not sufficiently simple, in the practical solution of the 
mechanical problem which it involves there are one or two points of 
difficulty which have constituted the despair of many inventors, and 
with which very few have succeeded in dealing successfully. The first 
of these is to secure such a construction as shall admit, without trouble- 
some complication, of the setting of the machine, as above appears to 
be necessary, to the numbers presented in the original problem ; and 
the next, to provide a simple expedient for carrying forward the tens 
found in the result of the addition of each order of figures to the order 
next higher. To these matters we shall presently return. 

Since the dawn of mathematical science in Europe the attempt to con- 
struct a machine capable of satisfactorily performing arithmetical oper- 
ations has occupied the attention of a great number of ingenious men, 
several of whom have been among the most celebrated of their time 
for originality of genius, and for the large contributions which they 
have made to the progress of science. Notwithstanding the force of 
intellect and the varied ability which, for some centuries, was thus con- 
centrated upon this problem, the history of the labors of most of these 
inventors amounts to little more than a history of successive failures ; 
and it is only within recent years that a really serviceable calculating 
machine has been at last perfected. The most successful machine of 
this class which modern ingenuity has produced — putting aside for the 
moment the " difference engines," such as those of Babbage and Scheutz — 
is probably the "arithmometer" of Mr. Thomas de Colmar, which was 
exhibited in the French section of the Exposition, where it was con- 
stantly the center of a curious crowd. 

In a lively little book, by Mr. Jacomy Regnier, prepared in the interest 
of this inventor, is contained a series of brief notices of those who had 
attempted earlier to walk in this difficult path. The earliest named 
belongs to the tenth century, and was no less considerable a person than 
Gerbert, archbishop of Eheims and chancellor of France, who finally 
became pope, under the name of Silvester II, but who, in early life, was 
an obscure shepherd in the mountains of Auvergne. Even while in this 
humble condition his inventive genius displayed itself in several striking 
modes. He constructed a hydraulic organ, of which the tubes were 
formed of bark skillfully detached unbroken from the branches of trees, 



632 PARIS UNIVERSAL EXPOSITION. 

while the blast was produced by the action of falling water. Finding 
it difficult to divide his day when his £ime-piece, the sun, was obscured 
by clouds, he constructed with his pocket-knife a clock, which measured 
very tolerably the hours, and which was the germ of an elaborate and 
artistic achievement of the same kind in later years at Magdeburg. 
This singularly ingenious peasant attracted the attention of an intelli- 
gent ecclesiastic, Geraud de Saint Cere, prior of the Benedictine mon- 
astery at Aurillac, who received him into his religious family, made him 
a monk, and sent him to the Moorish universities — then the most 
renowned in the world — of Cordova and Seville. A residence in those 
cities was at that time prohibited to Christians ; but Gerbert quietly 
took the habit of a Mussulman, followed diligently the course of studies 
in both universities, and returned to Barcelona in the year 968, thor- 
oughly skilled in the learning of the Arabian doctors, and the bearer 
of the most valuable gift which the West had yet received from the 
East, the Arabic numerals. 

Possessed of this powerful instrument of calculation, Gerbert was 
seized with an irrepressible desire to enlarge the value of the gift by 
relieving the possessor of the drudgery attendant on its use. He knew, 
it is asserted, that the Arabians had attempted the same thing before 
him, and that they had all failed; but this knowledge served only as a 
stimulus to his zeal. His impatience to embody his conceptions into 
form led him, during a residence in Rome, to apprentice himself to the 
trade of a turner. It was his conviction that so soon as he should be 
able to construct and to combine with his own hands the elements of 
his various devices, he could not fail to secure an early and an easy 
success. Unhappily his hopes were disappointed. The ingenuity which 
had triumphed over so many difficulties before was compelled to confess 
itself at last baffled. He constructed many calculating machines. They 
had all one common fault — they would not calculate. 

Albertus Magnus, ecclesiastic, teacher, master of the sacred palace, 
archbishop of Eatisbon, and finally, by preference, simple monk, was 
distinguished for his vast acquirements and for his restless scrutiny into 
the mysteries of nature. His zeal in the prosecution of an endless 
variety of objects, some of them no doubt substantial, but many of them 
visionary ; his knowledge, out of harmony with the dense ignorance of 
his age ; and the numerous curious experiments and wonderful discov- 
eries which marked the progress of his researches, won for him among 
his superstitious contemporaries the character of a sorcerer. He con- 
structed a human head of brass, which was reputed to have the power 
of responding to interrogatories; and it was affirmed of him that he was 
accustomed to consult this head as an oracle in the prosecution of his 
investigations. The sequel of the tale is eminently characteristic of the 
age to which tradition assigns it. Such an abominable contrivance could 
not fail to be regarded as an outrage upon the feelings of all right-minded 
persons, too shocking to be patiently endured ; and hence it occasions 



MECHANICAL CALCULATION — RODS OF NAPIER. 



633 



us no surprise to be informed that a blow from the indignant staff of the 
"angelic doctor," Thomas Aquinas, himself a pupil of Albert, brought 
sudden and deserved destructionu pon this monstrous monument of 
impiety. 

The imaginative author above referred to, Mr. Regnier, asserts, upon 
what authority it is difficult to say, that this head was nothing else but 
a calculating machine, and that the responses which it rendered were 
not sentences audibly uttered, but were merely the results of computa- 
tions presented in visible characters between its lips. 

The famous Roger Bacon, a contemporary of Albert, laboring like 
him also under the disadvantage of a reputation equally equivocal, con- 
structed likewise a head, possessing, as it was supposed, the same mar- 
velous endowment. The story of Friar Bacon's brazen head, and of 
the ruin which befell at once the invention and the hopes of the inven- 
tor, is among the most familiar of the legends which have come down to 
us from the thirteenth century. This, too, according to Mr. Regnier, 
was a machine which answered only to arithmetical questions, and 
which was constructed in a form so fanciful merely for the sake of im- 
pressing the spectators of its performance with the profounder aston- 
ishment. 

To descend to later times, the first form of apparatus, of which we 
have any authentic account, designed to facilitate, by mechanical means, 
the operations of arithmetic, is found in what are 
called the rods of Napier. The name of Napier, 
baron of Merchiston, is associated with some of the 
most useful inventions which have marked the pro- 
gress of mathematical science. Among these may 
be mentioned the system of logarithms, and the 
simplification of spherical trigonometry by the 
introduction of the well-known "analogies" ai d 
"circular parts." Lord Napier's contrivance for 
facilitating arithmetical computations, applied only 
to multiplication, and consisted of a set of rectan- 
gular rods, sometimes called "Napier's bones" from 
the material of which they were constructed, divided 
Fig 150. into squares or cells, nine in number upon each rod, Fig, 151. 
in which were written the products of the several digits in their order as 
they stand in the common Pythagorean table. Fig. 150 represents one 
of these rods, embracing the number and its several products by the 
nine digits taken successively. Each cell is divided by a diagonal line 
running downward from right to left. The original number itself, and 
the product, if it contains but a single digit, is written in the right-hand 
triangle thus formed. When there are two digits in the product, the unit's 
figure is written in the right-hand triangle, and the ten's figure in the left. 
When a number consisting of several figures is to be multiplied, a series 
of rods must be selected which carry these figures severally in their upper- 
most cells, and arranged side by side, as in Fig. 151, so as to present the 









1 ' 7 








> 

/ 

> 


A 

A 
A 


/9 


A 

i 


A 


A 


/8 


A 


4/ 


1/ 
/o 

X 


A 


A 


A 

/8 


6/ 

A 

A2 


1/ 
74 

/6 


A 


8/ 
Ax 


V 




^ ^ \ 



634 PARIS UNIVERSAL EXPOSITION. 

multiplicand complete in reading directly across. The product of this 
multiplicand by any digit will then be found in the row of cells corre- 
sponding to the multiplier; remembering that, in reading, the sums 
of the figures are to be taken which stand in the successive diagonal 
cells. 

It will be seen that the product of the multiplicand can only be taken 
by one digit at a time. The successive partial products, when the mul- 
tiplier contains several figures, must be written down and added accord- 
ing to the ordinary rules for multiplication in arithmetic. 

Though this contrivance is ingenious, it constitutes but a short step 
on the way to a calculating machine. The loss of time inevitable in the 
selection and arrangement of a suitable set of rods for any multiplication 
is too serious a disadvantage to allow the system to become practically 
useful. Many inventors diligently strove to remove this objection by 
attaching the columns of cells to cylinders, or to polygonal blocks of 
wood, capable of turning on their axes. One of these, Petit, employed 
at length but a single cylinder, with sliding columns, which could be 
pushed out of the general group, so as to present the proper combina- 
tion detached from the rest. But all these expedients were unsatisfac- 
tory, as it is evident that they must have been, since one important con- 
dition of the usefulness of the system is that the columns in use shall be 
as nearly as possible in juxtaposition. 

The contrivance of Petit excited the interest of a man since very 
famous in the scientific and literary history of France, the man to whom 
in our own time we have seen imputed, however absurdly, the merit of the 
greatest of the discoveries of Xewton — Blaise Pascal. Finding himself 
unable to improve upon the invention of Petit for perfecting the usefulness 
of the Napierian rods, Pascal conceived the bolder project of constructing 
a machine which should truly calculate. He succeeded in a manner 
which was not a success ; for his machine was formidably complicated, 
and the range of its capabilities was exceedingly limited. And yet. 
remarks the historian, of all the creations of this great man. there was 
none on which he more persistently wearied his genius, more unprofitably 
wasted his hours, or it may even be said, more rapidly wore out his life, 
than on this. 

Imperfect as was the machine of Pascal, it was regarded as a mar- 
velous conception, and it won for its author universal applause. Many 
ingenious artisans directed their efforts toward its improvement : among 
them, Grillet, horologer to Louis XIV. This accomplished mechanician 
succeeded to an important extent in simplifying the machinery of Pascal, 
and in reducing the construction to a form in which it might have been 
of practical utility had not its performance been limited to a very few 
places of figures. The author of this improvement made a secret of its 
mechanism, but exhibited it to the public for a fee. Its construction 
remains still unknown, and would have no present interest but for its 
relation to a little episode in the life of a much greater man than Grillet. 



MECHANICAL CALCULATION MACHINE OF LEIBNITZ. 635 

one of the greatest whom modern Europe has produced, the celebrated 
Leibnitz. 

Conti, himself a distinguished mathematician, said of Leibnitz, "He 
aimed to surpass all mathematicians. There is hardly a purpose of civ- 
ilized life for which he did not invent some machine ; but none of his 
machines succeeded." The applause with which all Europe rung over 
the achievement of Pascal, which was regarded as a triumph of genius 
wholly without a parallel, fell painfully on the ear of Leibnitz. He was 
now in the very zenith of a glory which few men by the mere force of 
intellect have ever attained. The Emperor of Germany, the Czar of 
Bussia, the Elector of Brandenburg, all the German princes, had lav- 
ished upon him dignities, pensions, honors ; all the academies of Europe 
enrolled him with eagerness on the list of their associates ; apparently 
there remained for him no scientific distinction further to attain ; and 
yet, in the midst of all his honors, the gifted, favored, courted Leibnitz 
was not happy. The machine of Pascal troubled his slumbers. He 
resolved to create a new one which should throw that marvelous achieve- 
ment into eclipse. This single project presently absorbed all his thoughts. 
Philosophy, chemistry, physics, mathematics, correspondence with the 
learned, relations with monarchs, everything he put aside that he might 
gather all his forces, and give his whole genius and his whole time to 
the service of this new ambition. For nearly four years he lived only 
for this one single end, to construct a calculating machine superior to 
that of Pascal. After having in some part perfected his device he sent 
the plans of it to the Royal Society of London ; and at a later period he 
laid them before the Academy of Sciences of Paris. According to these 
plans, the machine was designed to execute the four fundamental opera- 
tions of arithmetic. He had expended on its construction a sum of one 
hundred thousand francs; and yet the machttie was found after all to be 
poorly executed, uncertain in its operation, and incapable of performing 
an addition or subtraction extending beyond four figures. To complete 
his discomfiture, it began to be hinted, at first in timid whispers, and 
afterward in open and bold assertion, that the machine which had cost 
Leibnitz so much of his time and labor and money, was neither more 
nor less than an imitation, almost servile, of the contrivance of Grillet, 
a machine which had some time previously remarkably disappeared, 
having been disposed of by its inventor, no one knew how. The mechan- 
ical construction of this instrument was, as we have seen, never made 
publicly known. Whether Leibnitz, as was maintained and believed, 
had really become its secret purchaser, and whether, in despair of origi- 
nating anything better himself, he had finally determined to adopt it as 
his own, is a question which cannot, of course, now be ever satisfactorily 
settled; but one thing which is matter of history is the fact, that the 
machine of Leibnitz, for practical utility, was inferior to that from which 
he was asserted to have copied. 

The logarithmic scale of Edmund Gunter, first constructed in 1624, 



636 PARIS UNIVERSAL EXPOSITION. 

may be classed among the instruments designed to facilitate calculation 
by mechanical means. The divisions of this scale correspond to the 
numerical values of the logarithms of numbers. It reduces the opera- 
tions of multiplication, division, and the extraction of roots, to the addi- 
tion and subtraction of lines. In theory, its powers are very great; in 
practice they are comparatively limited, from the fact that the divisions 
must either be very small, or the dimensions of the instrument itself be 
too great for convenience. In its original form, an additional source of 
inaccuracy and loss of time was found in the necessity of employing a 
dividing compass in using it; but this disadvantage was removed in the 
modification introduced by Leadbetter in 1750, and afterwards attributed 
to Jones, in which were embraced two rules sliding side by side. A fur- 
ther improvement, made by Leblond, in 1795, and Gattey, in 1798, con- 
sisted in giving to the sliding rules the form of concentric circles. The 
circular form possesses the advantage of admitting a greater length of 
scale conveniently within the reach of the operator; but still, without 
greatly exceeding the dimensions to which, for any practically useful 
purpose, such a machine must be limited, it is impossible to secure results 
which can be relied on beyond three places of figures. 

To the list of those who from time to time attempted the construc- 
tion of calculating machines, properly so called, must be added the 
names of Sir Samuel Moreland, (1773 ;) Perrault, architect of the Louvre 
and of the Observatory of Paris, (1699;) the Marquis Poleni, famous for 
his masterly achievement of securing St. Peter's from ruin, after all 
other architects had pronounced the case hopeless, (1709;) Leupold, 
member of the Berlin Academy, (1727 ;) Olairault, illustrious French 
geometer, a member of the Academy of Sciences at eighteen years of 
age, (1750;) Lepine, distinguished horologist of Paris, (1725:) Boissen- 
deau, (1730 ;) Gersten, (1735 :) Pereire, (1750 ;) Diderot, (1760 :) Bowning, 
(1770;) Lord Stanhope, (1776;) Matthew Hann, (1777;) Miiller, (1781;) 
Abraham Stern, distinguished mathematician of Warsaw. (1811,) and 
probably many others. Of the effort of Diderot, Mr. Begnier. to whom 
we are indebted for much of the foregoing information, amusingly says : 
"Since the arithmetical machine, called Diderot's, has been described 
at length in the great Encyclopedia, we will say nothing about it here, 
but will content ourselves with recalling the fact that nearly all the 
savants of the Encyclopedia are reputed to-day to have contributed, with 
all their science and all their genius, to the creation of this clumsy 
affair, of which the memory of Diderot alone has long borne the respon- 
sibility." 

In the year 1822, a Erench inventor, Mr. Thomas (de Colmar,) pat- 
ented an invention, in which the problem of the calculating machine 
was first satisfactorily solved. This statement is not in conflict with the 
fact, which is not forgotten, that, in 1821, Mr. Babbage, of London, com- 
menced the construction, under the patronage of the British govern- 
ment, of the famous difference engine, of which the original promise 



CALCULATING MACHINES. 637 

was so great, but which has never been completed. The imperfect con- 
dition in which that remarkable machine has been left, is a consequence 
not of any fault in its design, but of the discontinuance by the govern- 
ment of the appropriations necessary for the continuance of the work. 
Mr. Babbage's machine was not intended to perform the ordinary opera- 
tions of arithmetic, and hence it is not in place to consider it here. 

Since the expiration of the patent of Mr. Thomas, many projects for 
machines of this description have been patented in Europe. It would 
be difficult at present to form a complete list of the inventors who have 
busied themselves with this fascinating problem. What is remarkable 
about them, however, is that the most are only known as projects, none 
of them having been successful in securing that kind of evidence of 
approbation from those who need such help which is furnished by their 
adoption in use ; while, of the few that have been received with the 
greatest favor, all have borrowed, more or less directly, the distinctive 
characteristic of the machine of Mr. Thomas. 

In the official general catalogue of the Exposition of 1867 there were 
enrolled the names of a number of exhibitors of calculating machines. 
Only two machines of this class, however, actually presented them- 
selves. One of these was exhibited by Mr. Oprandino Musina, of Mon- 
dovi, Italy, and was called by him a " pocket machine" for addition and 
multiplication. It was very small and exceedingly simple, being in the 
form of a rectangular solid, eight inches long and au inch square in 
cross-section. Looking upon the top there are perceived a row of aper- 
tures, through each of which may be seen a single figure. These fig- 
ures are inscribed upon the outer circumferences of as many small 
wheels or drums concealed in the box, which have their faces in the 
same vertical plane, and their axes horizontal and at right angles to the 
sides of the box. Upon the vertical side, toward the observer, there is 
an equal number of fixed dials, which carry a series of numbers, from 
at the top to 9; the whole circumference being divided into ten equal 
parts. A little index, like the hour-hand of a clock, on each dial, 
points, when the instrument is at rest, to the zero. Its position is then 
vertical. A button on this index permits the operator to turn it in the 
order of the numbers ; and as he turns, the corresponding drum in the 
interior turns also and to the same extent. It will be understood that 
the figures on the top record the result, while the little cranks, as they 
may be called, serve to the performance of the operation. The right- 
hand drum and dial answer to the place of units ; the next toward the 
left, to tens; the next to hundreds, and so on. 

Suppose we wish to perform addition ; we must first see that no char- 
acters appear in the openings at the top except zeros. Let it be 
required to add 267 to 431. We begin with 431, and turning the units' 
crank to the first division of the dial of units, the number 1 appears in 
the opening at top. The crank when released, returns spontaneously to 
zero, by the recoil of a spiral spring attached to its axis. It will be per- 



638 PARIS UNIVERSAL EXPOSITION. 

ceived, of course, that it turns the drum in the interior, by means of a 
ratchet and catch. The second crank, or crank of tens, is then turned 
to 3 and released ; and the third to 4. The number 431 then appears in 
full on the top of the box. The other number, 267, is then added in the 
same way, beginning with 7 in the units' place. Turning the first crank 
to the figure 7, the drum advances seven divisions, and as it was pre- 
viously advanced o/ie, the final reading will be 8. The next crank is 
then turned to 6, and the reading of the tens becomes 9. The third 
crank is turned to 2, and the number of hundreds reads 6. The sum of 
both numbers is then presented in the openings at top, and will be 698. 

In this example there has appeared, no necessity for carrying. But 
suppose to this sum, 698, it is proposed to add 875. As we turn the 
units' crank from toward 5, the number 9 first appears at top, and then 
the zero. While the crank is moving from 1 to 2, therefore, a unit must 
be carried from the first drum to the second. This is effected by a 
ratchet connection between the successive drums, which takes effect 
only once in each revolution, and when the drum on the right, or, as we 
may call it, the driving drum, is passing from 9 to 0. In the present 
instance the units' drum, after passing zero, goes on to 3, 13 being the 
sum of 8 and 5, and the 1 (ten) having been carried forward to the next 
drum. But here occurs a necessity for carrying again, since the reading 
of that drum is already 9. This 9 will accordingly change to 0, and the 
third drum, which marked 6, will exhibit the number 7. Turning now 
the second crank to 7, the drum which stood at advances to 7 also. 
And turning the third crank to 8, the 7 of the third drum becomes suc- 
cessively 8, 9, and (carrying 1,) and afterwards 1, 2, 3, &c. to 5. The 
total sum is then seen in the openings on the top to be 1,573. 

For multiplications, it is evident that each crank must be similarly 
moved as many times as there are units in the multiplier, before advanc- 
ing to the next. Since the movement of the crank is possible in only 
one direction, subtraction and division by means of this machiue are 
impossible. Subtraction may be performed by adding the arithmetical 
complement of the subtrahend ; which, if the machine were otherwise 
serviceable, would be a partial compensation for the disadvantage. This 
little contrivance hardly deserves, perhaps, to be called a machine. 

The other object of this class mentioned above as having been present 
in the Exposition was the invention of Mr. Thomas de Colinar, spoken 
of in the foregoing brief historical sketch. Although this invention, if 
judged by the date of its patent, is not recent, it is in this country so 
almost unknown that it has for us the character of an invention entirely 
new. At the same time the complete solution which it furnishes of a 
mechanical problem which had baffled the ingenuity of inventors, the 
rapidity with which it executes its operations, and the facility with 
which it may be managed, entitle it to something more than a cursory 
notice. 

The arithmometer of Mr. Thomas presents, externally, the appearance 



MECHANICAL CALCULATION THOMAS^ ARITHMOMETER. 6 )d 

of a neatly finished box ; the dimensions being determined by the num- 
ber of places of figures to which it is designed that the operations of the 
machine shall extend. This number is generally six, seven, or eight for 
each factor in multiplication, or twice as many in the product j but Mr. 
Thomas has constructed machines with as many as sixteen figures in the 
factors, and thirty-two in the products. For a machine of eight places 
in the factors, the measurement in length is about two feet, the breadth 
being nearly seven inches, and the depth three and a half. On opening 
the box, there appears, first, a metal plate having a number of grooves 
cut through it equal to the number of characters to be admitted into a 
multiplicand, parallel to each other in direction and at right angles 
to the length of the box. These grooves are graduated, and the divis- 
ions are inscribed with the characters from to 9. An index which 
slides in each groove can be placed opposite to any division. On the 
opposite side of the box from the operator, and beyond the grooves, are 
an equal number of small circular openings, one being opposite to each 
groove, in which the results of the operations are designed to appear. 
These results are formed of characters inscribed in a circular arrange- 
ment on the plane faces of as many disks which are concealed within 
the box, but present their successive characters at the openings as they 
revolve. At one end of the box in the interior is a small crank which 
turns horizontally, and is the means by which the machine is operated. 
In using the machine it must first be seen that no characters are visi- 
ble in the openings in which the result is to appear. The indexes are 
then set in their grooves opposite to the characters which form the first 
number to be used ; a single turn is given to the crank, and the same 
characters appear in the little windows opposite the several grooves. 
Another arrangement given to the indexes in the case of addition, and 
another turn given to the crank, add a second number to the first ; and 
this process may be continued as fast as it is in the power of the operator 
to effect the necessary changes of the indexes. For multiplication the 
expedition is greater. The multiplicand having been once set by means 
of the indexes, multiplication by any number is effected by the simple 
process of turning the crank as many times as there are units in that num- 
ber. And that nothing may be left dependent on the memory or sub- 
jected to the chances of forgetfulness on the part of the operator, there is 
another series of smaller windows in which appears the record of the 
number of turns given to the crank, as each successive figure of the 
multiplier is employed. When the multiplication by the unit's figure is 
complete, that by the tens follows, and is, by a simple expedient, added 
to the first. As, in written arithmetic, we begin the tens' product one 
place to the left, so in this mechanical process we transport the units' 
product one place to the right — the result being identically the same. 
In order to allow of this movement, the plate which carries the result, 
and which is independent of that to which the indexes belong, lifts out of 
connection with the machinery below, being hinged by a sliding hinge 



640 PAKIS UNIVERSAL EXPOSITION. 

on its outer edge, which permits it to be moved right or left. This plate 
having been raised by a button, moved one place toward the right, and 
readjusted, the multiplication by the ten's figure takes place as before, 
the number of tens in the multiplier being at the same time recorded in 
its proper little window. To multiply by the hundreds, thousands, &c, 
is only to repeat the operation just described for the tens. 

So much for the machine as it appears to the spectator ; now for the 
transmission of the motion. Each recording dial above described 
carries immediately beneath it a beveled pinion, which is geared into 
another beveled pinion on a horizontal arbor, its own axis being vertical. 
This horizontal arbor extends from beneath the dial directly across the 
box, and underneath the groove belonging to that dial with which it is 
coincident in direction. This arbor is square, or angular, and it carries 
a pinion which can slide on it from end to end, but cannot turn round 
without turning the arbor also. And immediately under the pinion is a 
barrel or cylinder having the same length as the grooves above it, upon 
the surface of which are projecting teeth or leaves extending longitu- 
dinally to unequal distances. On one-half the barrel there are no leaves 
at all. On the other half, the leaves form a series of nine in all, increas- 
ing in length from one-tenth of the length of the cylinder to nine- tenths. 
It is as if a full-leaved pinion of eighteen or twenty teeth had been 
originally made, and afterwards cut down, so as to present the limited 
number of unequal leaves just described. The effect of this construction 
will now be understood, and the understanding will be facilitated by 
reference to the little figure here annexed. Here, A represents a long- 
leaved pinion from which the leaves have been partially cut 
away ; and B represents a spur-wheel gearing into the pin- 
ion. It is obvious that if B is near the end A of the large 
pinion it will be acted on by only a few of the leaves of the 
pinion, while at the opposite end it will be acted on by them 
Fig. 152. all. There are twenty leaves in the pinion here represented. 
Only nine of these are needed in the machine of Mr. Thomas, the rest 
being cut away entirely ; and of these nine the lengths increase in the 
proportions just stated, so that the spur-wheel B, according to the posi- 
tion given it by sliding it on its arbor, may engage during a revolution 
of A any number of leaves, from one to nine j and may even, also, by 
being moved beyond the reach of any of the leaves, escape being acted 
upon by them altogether. 

It will now be seen what is the effect of sliding the indexes as 
described above, in the setting of the machine. Each of these indexes 
commands one of the little spur-wheels, B, and places it at that point in 
which it will engage as many leaves of the large pinion, A. as there are 
units on the graduated scale opposite to it. The revolution of A ad- 
vances the spur-wheel just so many teeth, and this spur-wheel, turning 
its arbor with it, transmits a movement of precisely the same number 
of places through the bevel gearing to the dial. 




MECHANICAL CALCULATION THOMAS'S ARITHMOMETER. G41 

It must now be provided that all the large barrel-pinions shall turn 
simultaneously. This is effected by means of a horizontal arbor extend- 
ing longitudinally along the box, and acting on the arbors of all the 
barrels by means of bevel- gearing. Finally, this longitudinal arbor is 
similarly driven by a vertical arbor at the right hand extremity of the 
box; a crank turning horizontally being attached to this vertical arbor. 
This last complication was unnecessary, since the crank might be 
attached directly to the end of the horizontal arbor ; but the inventor 
has preferred the construction actually employed, because it permits to 
inclose the crank in the box without detaching it ; and also because of 
the small altitude (three and a half inches) of the machine. 

Thus far nothing has been said of the provision for carrying for tens. 
This is effected by means of a mechanism upon the arbors of the barrels 
and spur-wheels above spoken of, and between the barrels and the dials, 
of which the parts are ordinarily out of gear, but which when brought 
as occasion requires to engage with each other, cause the dial to advance 
one place, after the advance regularly due to the revolution has been 
completed. The movement by which the parts are thrown into gear is 
produced by the action of a pin beneath the dial of the next place to 
the right, which pin is fixed at such a point as to operate just as the 
nine of that dial is giving place to zero. But no carrying takes place 
anywhere along the line until all the leaves of the barrel-pinions have 
completed their effect ; and this (because all those leaves are on one 
side of the barrels respectively, while the opposite sides are blank) 
occurs when the revolution is half completed. The carrying, if any is 
necessary, will then take place in the several orders of figures success- 
ively, beginning at the right. The propriety of this arrangement will 
appear when it is considered that the carrying from a lower order may 
itself be the occasion necessitating a carrying from the next higher 5 as 
was illustrated by the example employed in speaking of the machine of 
Musina. Moreover, as a little force is necessary in producing the move- 
ment required in carrying, it is important that the resistances should not 
be allowed to accumulate. This is prevented by making the movements 
consecutive and not simultaneous. In the machine of Musina no such 
provision has been made, and consequently, when several figures are to 
be carried at once, as may happen, for example, when a unit is added to 
such a number as 9999999, the united resistance is sufficient to endan- 
ger the strength of a delicate mechanism. This consideration explains 
why it was thought expedient to confine all the leaves upon the barrel- 
pinions to one-half the circumference. They thus accomplish their 
work in the first half of the revolution, and leave time to make all the 
subsequent movements of carrying consecutive. 

We thus see how addition and multiplication are provided for. It 

remains to consider the cases of subtraction and division. It has been 

stated that the recording dials are turned by a bevel gearing, the axes 

of the driving gear-wheels being horizontal, while those of the dials 

41 1 A 



642 PAEIS UNIVERSAL EXPOSITION. 

themselves are vertical. Xow when, by a mechanism of this kind, a 
rotation round a horizontal axis is transmitted to a wheel having its 
axis vertical, the direction of rotation which this latter wheel will 
assume will depend, on the limb by which it is engaged. If attacked on 
one side of the center it will turn one way; if on the other side the 
other way. In the machine under consideration each of the horizontal 
arbors beneath the dials carries two bevel gear-wheels connected together 
and capable of sliding together on the arbor, but placed so far apart 
that when one of them engages the pinion of the dial wheel, (which is 
between them.) the other is thrown out. This whole system of sliding 
gear-wheels on all the arbors is commanded by a frame-work and lever 
arrangement, such that, by moving a button, the direction of rotation of 
all the recording dials may be simultaneously reversed ; while the move- 
ment of the driving crank is always in the same direction. It will be 
seen that it would not do to turn the crank itself backward and thus to 
reverse the rotation of the recording dials by reversing that of the 
barrel-pinions. This would be a simple and entirely eligible mode of 
proceeding if nothing were to be considered but the turning backward of 
the several dials through the numbers of places marked by their corre- 
sponding indexes; but as it woidd neutralize the whole arrangement for 
carrying, by making the action of the barrel-pinions to take place in 
the last instead of the first half of the revolution, it is inadmissible. 
The processes of subtraction and division now hardly require further 
explanation. The first of these operations requires no other manipula- 
tion but that which is used in addition. For division it is expedient, 
before placing the dividend, to lift the plate carrying the recording dials 
and to carry it as far as possible to the right. The dividend is then 
introduced by setting the indexes to its proper figures, and the reversing 
button being at addition, giving one turn to the crank. The button is 
then to be placed at subtraction, and the divisor marked by the indexes 
just beneath those left-hand figures of the dividend which suffice to 
contain it. The operator turning the machine watches the diminishing 
figures of the dividend until they become less than those of the divisor 
beneath them, when he ceases to turn and moves the plate carrying the 
dials one place to the left. In the mean time the macliine itself has 
recorded his first quotient figure. The other quotient figures are obtained 
in like manner, and when the operation is complete, the remainder, if 
any, will stand in the place of the dividend. 

The expedition with which these operations may be conducted is 
marvelous. It seems to be thought by some that an arithmetical 
machine is of no practical use, because it is not customary in point of 
fact to perform large multiplications or divisions by purely arithmetical 
processes. As computations are usually conducted, logarithms are 
invariably resorted to for such purposes. But these are precisely the 
multiplications and divisions in which logarithms, with all their util- 
ity, fail to furnish the required results without an amount of trouble- 



MECHANICAL CALCULATION — THOMAS S ARITHMOMETER. 643 

some interpolation which it is a weariness to the calculator even to 
think of. No tables of logarithms extend beyond five places of natural 
numbers. And even those which are furnished with the auxiliary and 
minor tables in the same page for facilitating interpolation, exact of the 
most expert arithmetician a greater expenditure of time, in finding and 
writing the logarithms and in afterwards looking out the natural num- 
bers, than is necessary to perform the same problem by the machine 
three times over. In these transcriptions and secondary computations 
for interpolation, there are, moreover, repeated opportunities for the 
intrusion of error ; but the machine, when its original adjustments are 
correct, never makes a mistake. 

In multiplying and dividing by logarithms, we often, on account of 
the trouble, just spoken of, of interpolation, disregard entirely the small 
decimals of our products, and fail to pursue our quotients to many places, 
and yet such neglect sometimes vitiates a result, and oftener leaves a 
feeling of dissatisfaction. The machine will give an answer to a number 
of places embracing the full extent of its range with absolutely the same 
facility, and with the same unerring accuracy, as to two or three only. 
The writer, as the result of a pretty heavy experience in the use of log- 
arithms, and of a trial for a limited time of the calculating machine of Mr. 
Thomas, is fully satisfied in his own mind that, as an aid to the ordinary 
calculations of business, but still more to the laborious computations into 
which the man of science is often compelled to enter, this machine has a 
very substantial value, and cannot fail to be more and more highly appre- 
ciated the longer it is used. 

It has been observed that the range of the ordinary calculators of 
Mr. Thomas is limited to six or eight places in the factors, and twelve 
or sixteen in the product. But it is easily seen how, with little trouble, 
this range may be practically extended. Suppose that, with an eight- 
figure instrument, it is desired to multiply two numbers extending to 
twice as many places; that is, to sixteen figures each. The first eight 
figures of the multiplicand may be treated by themselves, being assumed 
to have eight zeroes after them. These eight may be multiplied by the 
first eight of the multiplier, assumed in like manner to be followed by 
eight zeroes. The product, found in a few seconds, must then be writ- 
ten down with sixteen zeroes following ; and then the same eight figures 
of the multiplicand may be multiplied by the second eight of the multi- 
plier, the product being written down under the former, but with only 
eight zeroes. Thirdly, the second eight figures of the multiplicand may 
then be successively multiplied by the first eight, and the second eight 
of the multiplier, as before; the former product being written down 
with eight zeroes, and the latter with none. The four products added 
as they stand will furnish the total product required. 

The following is an example of this kind actually performed with the 
machine for the express purpose of this illustration. From beginning 
to end, the time occupied in obtaining the result was six minutes, of 



644 PARIS UNIVERSAL EXPOSITION. 

which a considerable part was occupied in transcription. Eequired, to 
multiply the number 9582653477982169 by 8795631824673912. Divide 
the multiplicand into 9582653400000000 and 77982169. Divide also the 
multiplier into 8795634800000000 and 24673942. 
First product ------ 84285490973448120000000000000000 

Second product ------ 236444546748400800000000 

Third product ------ 685902445489374200000000 

Fourth product ------ 4924425475475428 

Total- ------- 84285494895762444434600475475428 



Of the six minutes occupied in performing this operation, less than 
two are consumed in the strictly calculating' part ; the setting of the 
indexes, and the clearing of the tables between the successive multipli- 
cations requiring some time, and the transcription and summation occu- 
pying the rest. Of course a problem like this is beyond the reach of 
any logarithmic tables existing; and if it were not, the logarithmic 
method would be very much slower and greatly more troublesome. 

A comparative example in which the tables will furnish by interpola- 
tion a result very nearly accurate is the multiplication of four figures by 
f onr — as for instance, 8,659 by 3,973. The machine gives the product 
34,402,207 in less than half a minute, including the time occupied in 
preparation. It will be an expeditious operator who will reach the result 
by means of logarithms in less than two and a half minutes ; and then 
he will find it inaccurate in the last place — the tables giving 34,402,208 ; 
an error which he might correct by considering the unit's places of the 
factors, if he could have entire faith in the truth of the preceding 
figures. 

Of the numerous calculating machines which have been proposed or 
constructed since that of Mr. Thomas became an ascertained success, 
those of Messrs. Maurel & Jayet, of France, and of Mr. Staftel, of Russia, 
are the only ones which, so far as is known, have solved the problem in 
a manner entirely satisfactory. Both of these employ a mechanism in 
which the barrel pinions of Mr. Thomas are in substance introduced ; 
and hence they cannot be regarded as presenting original solutions. In 
both of them the mechanism is too delicate for ordinary rough usage, 
and they are both costly. 

It has been mentioned above that two difficulties attend the construc- 
tion of a machine for arithmetical calculations. The first is to adapt it 
to receive any numbers within a given range on which it may be desired to 
operate. A counting machine adds at each movement invariably the 
same number. This is ordinarily a unit, but it may be made as well any 
number of units; and provided this number is to be continually added 
without change, no machinery is necessary to accomplish the object but 
such as is of the simplest description. But when the number to be 
operated on is different for every new operation, it is extremely difficult 
to devise a simple mechanism capable of adapting itself to this condition. 



MECHANICAL CALCULATION BABBAGE's ENGINE. 645 

Mr. Thomas's system of barrel pinions was the earliest expedient by 
which the difficulty here signalized was satisfactorily overcome; and 
Ave have seen that it has been more or less explicitly reproduced in the 
later machines which have equally succeeded. 

The other difficulty is that which is encountered when it becomes 
necessary to make provision for carrying for tens. In counting machines 
each of the figure dials acts, at the proper point in its revolution, upon 
the one next higher. This is the case also in the calculating machine of 
Musina, described above. But, in counting-machines, the addition is 
made always to a single dial, the lowest in order ; and when it is neces- 
sary to carry from this to the next, it finds that one at rest. In an 
efficient calculating machine, additions are simultaneously made to all 
the dials ; and if, in carrying, each acts directly on the next, its action 
will often arrive at a time when that one is in motion, so that the two 
actions will interfere, or the carrying action will fail to take effect. The 
only remedy, while this direct action of one dial upon another is main- 
tained as part of the system, is to cause the dials to move successively, 
as in the machine of Musina ; an expedient which so far protracts the 
time of the operation as to neutralize in great measure the advantage. 
The alternative is to reject the direct action of dial upon dial, and to 
introduce a mechanism which may he prepared for action at the moment 
when the necessity of carrying occurs ; but which shall not act until all 
the dials have completed the movements which the setting of the 
machine requires. This mechanism then taking separate and subsequent 
effect will complete the operation. That the special branch of the problem 
here considered is not simple, is illustrated by the fact that, since the 
time of Gerbert, it has occupied ineffectually the attention of so many 
ingenious men; and that Babbage himself confesses that it was the 
source of his greatest trouble in the construction of his great difference 
engine. 

The purpose of this engine, and of the similar machines constructed by 
G. Mr. Scheutz, of Stockholm, of which one is at the Dudley Observatory 
in this country, and another in the office of the registrar general, in Lon- 
don, is not to perform the simple operations of ordinary arithmetic, but 
to compute the extended tables required for astronomical and other pur- 
poses, in which the successive numbers form terms of a series connected 
by a law expressible in a general formula. The calculation of these num- 
bers by the ordinary methods is an operation involving immense labor, 
and the results are liable to be vitiated by the errors to which even the 
most expert arithmeticians are occasionally liable. Supposing, more- 
over, that the computations are entirely correct, there remains the pos- 
sibility of errors of the press, which the utmost vigilance is not always 
sufficient to prevent. It was, therefore, a part of Mr. Babbage's plan 
not only to compute the numbers by machinery, but also to impress them, 
when completed, upon a plate from which they might be directly printed, 
or upon a matrix from which such a plate could be cast. 



646 PARTS UNIVERSAL EXPOSITION. 

The process by which the computations are made is founded on what 
is called in algebra the method of differences. It is demonstrable that, 
when a series of terms is calculated from a formula, by giving to a vari- 
able quantity in this formula equal successive increments, and when 
from these terms a series of differences is formed by taking each term 
from the next, and a second series, by taking the differences of the dif- 
ferences, and a third by operating on the second in like manner, an order 
of equal differences will be reached at last, so that the next succeeding 
series will be zeroes. The number of orders of differences in a purely 
algebraic series will be equal to the index of the highest power to which 
the variable is involved in the given formula. Let the formula be — 

ax + b 
and put a = 2, b = 3, and x (the variable) = 0, 1, 2, 3, &c, successively, 
and we have the terms, 

Series ----- 3 5 7 9 11 13 15 &c. 
Differences --- 2 2 2 2 2 2 

Let the formula be — 

x 2 + ax + b 
and we shall have two orders of differences as follows : 
Series - - - - 3 6 11 18 27 38 51 &c. 

1st differences - - 3 5 7 9 11 13 

2d differences - - 2 2 2 2 2 

Take the following formula, putting c = 4 

«r 3 — ax 2 + ox -\- c 

Series - - - - 4 6 10 22 18 91 16(3 &c. 

1st differences - - 2 1 12 26 

2d differences - - 2 8 11 20 

3d differences - - 6 6 6 

In like manner a series formed on the folio win: 
of differences : 

#*— 2# 3 -f-4# 2 — 3a?.+4. 

Series - - - 1 1 11 58 181 D 4,6-i E 991 1891 D 3308 £ . 
1st differences - 10 11 126 c 280 d 530 900 c llll d 
2d differences - 10 31 82 B 151 c 250 370 B 511 e 
3d differences - 21 48 A 72 b 96 120 A lllx, 

4th differences - 21 21 a 21 21 24 a 

Suppose that in this series we had only the first five terms, ending 
with 181. This term we mark d, and we have a series of differences 
marked c, Z>, a, o, in an oblique downward line. As the fourth differ- 
ences are all eqiuf, we may write 21 A next after 24 ; and by the law of 
construction we know that this difference added to the one marked a 48 
will give the difference marked b (72). Then b added to B will give e : 
and c added to c will give d ; and finally, d added to the term d will 



16 


72 






26 








6 








g will 


give 


four 


orders 



MECHANICAL CALCULATION. 647 

give e (404). Thus, by a series of four additions, we obtain any term when 
we have the series of differences leading up to the last term found. 
And as the effect of the successive additions is to carry on the successive 
series of differences precisely as it extends the main series, when one 
term has been found by this process, the extension may go on in the 
same way indefinitely. The letters a, A, ft, b, c, c, &c, annexed to the 
differences further to the right, lead from the term 1894 to the term 3308 
by the same kind of zigzag movement. 

A machine, therefore, constructed to make these additions will com- 
pute any series of tabular numbers formed on such a law so soon as a 
sufficient number of the initial terms of the series have been computed 
in advance, to furnish differences of all the orders. In this case five 
terms are necessary. If a series has more orders of differences than 
four, these, in the cases which occur in practice, are very small, and 
rarely affect sensibly the numbers required in the tables. The engine 
of Scheutz employs four orders of differences, and computes the tabular 
numbers to fifteen or sixteen places of decimals, of which only the first 
eight or ten are printed. Any error from the neglect of fifth or higher 
differences will be lost among the neglected decimals ; and when the 
process has been carried so far as to endanger the accuracy of the figures 
retained, the machine is set anew. This will only be necessary when 
the accumulation of fifth differences exceeds unity in the fourth. 

To explain the construction of these engines without very full draw- 
ings would be impossible. The design of this notice is simply to show 
in what manner they effect their results by a series of additions. For 
each order of differences there is a distinct set of number- wheels. The 
numbers on the wheels belonging to fourth differences are added to those 
already on the wheels belonging to the third ; these in turn to those of 
the second, and so on. Inasmuch as a wheel which is receiving an addi- 
tion cannot at the same time be transmitting one, the mechanism is so 
contrived that the even differences (fourth and second) are added to the 
odd (third and first) by one movement, and the odd differences are car- 
ried forward by a succeeding one. 

The numbers expressive of the completed term are presented in types 
which impress the characters in a material suitable for forming a matrix. 
This material is a kind of papier mache, such as is now extensively 
employed in stereotyping for the purposes of the ordinary letter-press 
The type are made of steel and are presented downward, the tablet 
carrying the plastic substance being raised at the proper moment by an 
eccentric to receive the impression. After each impression the tablet 
advances so as to present a fresh surface at the proper distance for the 
next impression. The entire surface of the plastic material is rubbed 
with black lead to give it smoothness and facilitate casting from the 
impression a stereotype plate of the ordinary form. When such a plate 
has been successfully cast the results of the computation are secured 
precisely as the machine gives them. 



648 PARIS UNIVERSAL EXPOSITION. 

The Sclieutz machine in the office of the registrar general in London 
has performed much useful work in the computation of tables. At the 
time of the Universal Exposition of 1862, in London, it was in such 
constant requisition that it could not he spared long enough to be made 
a part of the Exposition, to the interest of which it would have so 
greatly contributed. 

Mr. Babbage has projected a calculating machine of much higher 
powers than the difference engine, which he calls the analytical engine. 
The object of this is to develop algebraic expressions and to tabulate 
the numerical value of complicated functions when more variables than 
one are made to alter their values. It is said that the designs of this 
engine have been prepared in detail, and Mr. Babbage himself, in his 
latest book, expresses a hope that it may yet be constructed ; but the 
undertaking is, in a pecuniary point of view, a formidable one, and there 
is reason to apprehend that he may be disappointed. 



ADDENDA 



ESTIMATED VALUE OF ATMOSPHERIC PRESSURE. 

Iii tlie calculations of pressures, on page 80, the pressure of the 
natural atmosphere is taken at 2116.8 pounds per square foot. If we 
assume, as is commonly clone, the mean atmospheric pressure to he 15 
pounds per square inch, the pressure per square foot will be 21G0 pounds. 
It is nearer to the truth to take the mean pressure at 14.7 pounds ; and 
it is upon this assumption that the determination is made for the purpose 
of the calculations above referred to. This statement was appended in 
the original manuscript to the passage on page 80, and was designed to 
appear on that page as a foot-note ; but the note was accidentally omitted. 

THOMPSON'S ROTARY STEAM-ENGINE. 

In the description of Thompson's differential rotary steam-engine, 
commencing on page 87, it is remarked that " it will be seen by com- 
paring these figures that there are two pairs of pistons, each pair being 
attached to a core which occupies but half the length of the cylinder in 
the direction of the axis." The comparison of the figures given does not 
illustrate the last part of this statement ; and the reason of the disa- 
greement between the description and illustration is, that one of the 
wood-cuts designed for insertion in that place, having been accidentally 




aeff™ 



mislaid, was omitted. This cut is here supplied. It represents the 
engine in elevation, with a longitudinal section of the cylinder, and of the 
elliptical gear-wheels which are directly driven by the pistons. One of 
the pairs of pistons is seen in complete section, attached to a core which 



650 



PARIS UNIVERSAL EXPOSITION. 



occupies but half the length of the cylinder. The other pair is out of 
the plane of the section, but the section of its central core is presented. 
This figure shows also, in longitudinal section, the cylindrical valve 
exhibited in cross-section in Fig. 16, and referred to on page 93. The 
position of this valve, as shown here and in Fig. 16, is that in which the 
steam is shut off. The engine is started by turning the crank forty-five 
degrees to the right or to the left. If it be turned to the left, the steam 
will enter and leave the engine in the direction of the arrows in Fig. 16, 
and the rotation will be from left to right. If turned in the contrary 
direction, the rotation will be from right to left. The shaft whicli car- 
ries the pulley is directly behind the piston shafts. 

In the equation in line 11 of page 91, relating to this engine, there is 
some error of spacing which may create a little confusion, but a compar- 
ison of the equation with the preceding proposition will readily suggest 
the necessary correction. 

fourneyron's turbine wheel. 

The description of the Fourneyron turbine wheel, on page 110, was 
accompanied in the original by a drawing, showing the relation of the 

directrices of the issuing wa- 
ter to the floats of the wheel ; 
but this unfortunately was not 
at hand when the pages were 
made up for the press, and it 
was accordingly omitted. 

The figure is not. perhaps, 
necessary to the intelligibility 
of the description; but as it 
has since presented itself, it is 
here subjoined. In this figure 
the interior and deeply shaded 
part represents the base of the 
closed cylinder containing the 
volume of water. The exte- 
rior annulus, shaded more 
lightly, is the outer portion of the wheel carrying the floats. The axis 
of the wheel is seen in projection in the center, surrounded by the pro- 
tecting cylinder which keeps it free from the water. The directrices, 
which are fixed firmly within the water cylinder at the base, are repre 
sented by lines curving.from right to left, while the floats have a con- 
trary curvature ; so that, at the several points of intersection, the tan- 
gents of the respective curves are nearly at right angles to each other. 
Each alternate directrix extends from the central to the exterior cylin- 
der. The intermediate ones have less than half the length. It is obvi- 
ous that, with the arrangement represented, the rotation of the wheel 
will be from right to left, in the direction indicated by the arrow. 




ERRATA, 



Some errors have, unfortunately, crept into the impression of the fore- 
going report. Only such are here noticed as are likely to mislead : 

Page 30, line 13 from top, for BCC'B read BCC'B'. 

Page 35, line 36 from top, for A and B, read A and C. 

Page 44, line 32 from top, for 360.98 read 370,980. 

Page 45, line 5 from top, for maximum density, read density at maximum temperature. 

Page 45, line 5 from top, for minimum, read atmospheric. 

And in the analysis which follows, for AL read al, and v. v. throughout. 

Page 47, line 3 from top, for 450° read 482°. 

Page 52, line 28 from top, for can run, read can be run. 

Page 62, line 3 from bottom, for twofold, read something over. 

Page 94, line 10 from bottom, for a read n. 
. Page 111, line 11 from top, insert "equal" before "cells," and omit the remainder of the 
sentence. 

Page 115, in legend of cut, for containing read controlling. 
• Page 133, line 6 from bottom, for two read twelve. 

Page 137, line 18 from top, for 1837 read 1857. 

Page 138, line 2 from top, for one one-hundred-and-sixty-fifth, read one six-hundred-aod- 

thirty-fifth. 

- Page 146, line 3 of note, insert -r-1500 in first member of equation. 

Page 146, line 5 from bottom, Jst formula, \ ,,.-,. ^ t -, r , , •,• 

■r, -,„ ,. „ n , «■-, p r reverse the. indices and 1 of letters within 

rage 14b, line 6 from bottom, 2d formula, > ^ . , , 

I trie brackets. 

Page 146, line 9 from bottom, 2d formula, ) 

Page 149, line 17 from bottom, for thirty-six read fifty-six. 

Page 156, line 4 from bottom, for m read p. 

Page 158, line 1J from top, for X read -f-. 

Page 158, line 29 from top, for 3,922 read 3,939. 

Page 159, line 7 from bottom, for two read four. 

Page 174, line 7 from top, for volume read column. 

Page 178, line 2 from top, for centre read circle. 

Page 189, line 10 from bottom, for E read B. 

Page 192, line 9 from bottom, for at read to. 

Page 222, line 14 from top, for G read a. 

Page 402. — The note on this page belongs on page 395. 

Page 465, line 10 from top, for copper read silver. 

Page 477, line 3 from bottom, for N=h 2v=n2r 1 read N=«2"=n2 r— l . 

Page 494, line 18 from bottom, for dra : Dn read d n : D . 

Page 510, line 4 from top, for synchronous read isochronous. 

Page 581, line 17 from bottom, for F' read F,. 

Page 620, line 5 from top, for one three-thousandth read three one-thousandths. 



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INDEX 



A. 

Tage. 

Accumulation of force by means of water under heavy pressure 151, 152 

in fly-wheels — the Mahovos 153 

Acoustics 499 

Acoustic flames 509 

Achard's electric brake 273 

prize awarded by the Academy of Sciences of France 275 

Aerial motors, advantages of 119 

number of exhibitors of 120 

Agglomerated coal 309 

machines for making 310, 311 

use of, on railways and by steamers 311 

Air, resistance of tubes to flow of 1 37 

transmission of force by compressed 136-150 

Air-pump, Giessler's, without valves 490 

Kravogl's mercurial 492 

Richard's, without valves 493 

Richard's eight-barreled 495 

Deleuil's free piston 497 

Alauzet's printing press .. 433 

Albertus Magnus, calculating machine 633 

Alcohometer and volumeter of Siemens and Halske 220 

Allemand's brick machine 253 

Ammoniacal gas-engines, principle of construction of 70 

advantages of 73 

Frot's 73 

Delaporte's 75 

economy of, compared with others 76 

Ammoniacal freezing apparatus 368, 370 

Amsler's planimeter, theory of 625, 626, 627 

Analytical engine of Babbage 648 

Andrews & Brother, Messrs., centrifugal pump of 187 

Andree, Mr. L., models of densimeters in aluminum bronze 483 

Anemometer, Secchi's self- registering 574 

Annular brick furnace 357 

Appold, invention of centrifugal pump by 176 

Armor-plates, forging of, at Atlas Iron Works, (note) 8 

Armstrong. Sir William, method of accumulating force 151 

Armstrong's dovetailing machine 240 

Artificial stone 298 

Astronomical clock, Bond's 471 

Atlas Iron Works, armor-plates manufactured at 8 

Aubin's improved mills tones - 279 

Aurora borealis, De La Rives's apparatus 561, 562 

Automatic regulators of the electric light 417 

Autodynamic elevators, Champsaur's 172 

Reynolds's water-jet elevator 175 



654 INDEX. 



B. 

Page. 

Babbage, difference engine of 636, 645, 648 

analytical engine of 648 

Babinet, Mr. , report on Marval's heating apparatus 349 

Bailey light-house, Wigham's gas-light at 408 

Baking by Marval's heating apparatus 346 

Balances 484 

tabular statement of sensibility of 485 

Balbeck's telernetric double telescope 585 

Ballast Board of Dublin 411 

Band-saw, Perm's 245 

Bardonneche, (Mt. Cenis,) transmission of force by compressed air at 142 

Bardonneche, (Mt. Cenis,) construction of compressors used at 144, 145 

Barlow's planetarium .'. 471 

Barometer, Father Secchi's self-registering 572 

Barrel-making machinery ...- 247 

Bashforth's electro-chronoscopic apparatus 568 

Bathometer, an instrument for deep-sea sounding 609 

Beequerel, Mr., comparison of the electric light with others 421, 425 

thermo-electric battery of... 560 

Beet-root sugar, use of Robert's diffusion process in making 324 

Behrens, rotary steam- engine of . 83 

Belou, hot-air engine of 45 

Bengal, mode of producing ice in 364 

Benton, Colonel James G., electro-balistic pendulum of 565 

Berard's process for the production of steel 295, 353 

Bertsch's electrostatic induction machine 554 

Bessemer steel, process 284 

properties which the products exhibit 257 

statements upon the value and importance of invention of 288 

Austrian and Swedish exhibitions of 289 

bridge made of, over the Seine 293 

Beton agglomere 298 

method of mixing and using 300 

buildings constructed of 301 

crushing weight which it will resist 302 

Binocular microscopes 538 

Birmingham Company's electro-magnetic engine 126 

Bisulphide of carbon, use of, for extraction of oils 319 

Blowing machines, exhibition of 191 

Lloyd's noiseless fan 191 

Schiele's compound blowing fan 1 92 

Evrard's rotary compression blower 193 

Root's compression rotary blower 193 

Thirion's hydraulic pressure blower 1 93 

Boiler feeders 232 

Bond's astronomical clock and chronograph 471 

Borie's brick machine. .. 234 

Bottle-washing and corking machine 206 

Boulet Brothers' brick machine '-'34 

Bourdon's dynamometer 1 65 

Bourbouze, Mr., machine of, for illustrating the laws of falling bodies 489 

Brakes for rail cars, Achard's electric 273 



INDEX. C55 

Page. 

Brakes for rail cars, use of the Mahovos as a brake 1 59, 1G0 

safety brakes 349 

Bread-baking 1 by Marval's heating apparatus 349 

Brettes's electro-chronoscope 5G6 

Breval, Mr., rotary steam-engine of 95 

Brick, annular furnace for the manufacture of 357 

cost of production in Hoffman's furnace compared :\7>[) 

Brick-making machines 251-254 

Bridge of Bessemer steel over the Seine 294 

Bronzed iron, Tucker's 329 

Broom, mechanical, for street sweeping 275 

Brown, John & Co. , exhibition of Bessemer steel articles 288 

Buoys for lifting vessels ^ 337 

Butt hinges for doors, machine for making 350 

C. 

Calculating machines 629 

attempts to construct 636 

Babbage's difference engine 636, 645 

exhibitors of, at Exposition . 637 

arithmometer of Mr. Thomas . '.' 636, 633 

solution of problem of construction of 636 

Musina's pocket machine 637 

range of Thomas's calculators 643 

examples of rapidity of calculation 644 

difficulties atttending construction of. 644 

Scheutz's difference engine 645, 647 

Calculating machines, method of differences 646 

•Babbage's analytical engine 648 

Calles's hydro-aero-dynamic wheel 134, 135, 136 

Carre, Mr. E., sulphuric acid ice, apparatus of 366 

Carre, Mr. Ferdinand, ammoniacal freezing, apparatus of 368 

Carret, Marshall & Co., Messrs., water-engine of 101 

Cathetometers 614 

Cazal's electro-magnetic engine T25 

Cazenave & Company's brick machine 254 

Centrifugal pumps, invention of, by Appold 176 

principle of construction of • 176 

Gwynne & Co.'s 177 

Neut & Dumont's 1 83 

Coignard & Co.'s 185 

Andrews & Brother - 187 

Champsaur's autodynamic water elevator 171-174 

Chalopin's machine for corking bottles %66 

Chenailler's universal evaporator 

Chenille, manufacture of, in France and England 

Chenille-making machine *°° 

Chester's Holtz electrostatic induction machine 553 

Chollet-Champion's hydraulic press 196 

Chollet-Champion's mechanical press 

Chronograph 

Chronoscopes, electro 

Clang-analyzer, Koenig's 

Clement's water-meter ~~"* 



656 INDEX. 

Page. 

Cloth-drying- by machinery,' Tulpin's machines 271 

Coal, agglomerated for fuel 309 

Cochran's water-meter 225 

Coignard & Co., Messrs., centrifugal pump of 185 

Coignet, Mr. , beton agglomere 293 

Cold, artificial production of 361-3^4 

useful applications of 362 

Color printing presses 436 

Colladon, Mr., floating water-wheel of 109 

Cool, Ferguson & Co.'s barrel-making machinery 247 

Commutators for magneto-electric machines 420 

Compasses, nautical - 603, 604 

Comparators 615 

Compressed air, employed for the transmission of force 1 35 

resistance of tubes to flow of 138, 137, 138, 148 

power of varies as the product of its pressure and its volume 138 

engines and machinery for compression 144, 145 

effects of the heat developed in the compression of 146 

economy of transmitting power by 148 

transmission of force by, and by cable, campared 149 

Composing machines 451 

Compositor, Flamm's typographic 449 

Concrete Stone Company, process of making stone by 305 

Continuous freezing apparatus 370 

Coque, Mr. A., peculiarities of construction of water-engine of 105 

Corset- weaving machinery 256, 257 

Coscia, experiments at, on resistance of tubes to flow of air 137 

laws deduced from experiments at 137 

Cotton-gin, consequences of the invention of 5 

Counterpoise, hydraulic, of Mr. fidoux 308 

Creamer's safety-brakes for rail cars 272 

D. 

Dabbadie's theodolite 596 

Danaid, the, description and advantages of 117 

Davidson, George., spirit-level sextant 600 

David & Company's brick machine 252 

Deep-sea sounding*, velocity of descent of apparatus for 609 

Trowbridge's apparatus 605 

Dehaynin's machine for making agglomerated coal 310, 311 

Delcambre's composing machine 453 

machine for distributing type 455 

Deleuil, balances exhibited by 4^7 

free piston air-pump of 407 

De La Rive's auroral apparatus 562 

Delaporte, ammouiacal gas-engine of 76 

De la Roche Tolay, Mr., diamond perforator of 103 

Delaunay, Mr., description of water-engine at Huelgoat, by 100 

Densimeters 488 

Desguffe and Ollivier's sterhydraulie apparatus 198-204 

Detectors, electrical, applied to power looms 207-270 

Devisseber's sugar-cutting machine 200 

Diamaguetism, large electro-magnet for experirrents in 501 

Diamond perforator, construction of, and application of hydraulic motor to 104 



INDEX. 



65' 



Page. 

Discovery and invention, relation of, to each other 17 

Distributing machines 454 

Dividing instruments 613 

Diving bells 334 , 335 

Diving apparatus of the New York Submarine Company 336 

of Rouquayrol & Denayrouze 338 

regulator for maintaining equality of pressure 339 

pressure of air within and outside of the regulator 341 

depth to which a diver can descend 342 

pump for charging reservoirs with compressed air 343 

Division of labor, effect of, in stimulating invention 3 

Door, opening both ways 279 

with mechanical plinth 280 

Doumoulin-Froment, microscopic engraving by 620 

Dovetailing machine, Armstrong's, New York 240 

Zimmerman's, Prussia 241 

Ganz's, Hungary 24 1 

Drasche, Mr. Henry, exhibition of terra-cotta objects, by 359 

extent of production of brick 359 

Duboscq, Mr., exhibition of spectroscopes . 527 

Duboy's water-meter , 222 

Dutartre's press for printing colors 436 

Durand's brick machine 252 

Dynamic electricity 555 

Dynamo-electric machine, Ladd's 427 

Dynamometers, construction of 162 

Prony 's friction dynamometer 163 

* Taurine's 164 

Bourdon's 165 

Hirn's pandynamometer 166 

E. 

Earle, Mr. Oscar T. , steam pump of 1 70 

fidoux, Mr, Leon, elevator of 204 

hydraulic counterpoise, system of - 208 

Elastic media, relative economy of, discussion of 77-82 

Electricity, static induction apparatus, Varley's 546 

Topler's 549 

Electricity, hydro-electric batteries 555 

Electricity, engraving by 46 1 

Electrical detectors applied to power looms 267-270 

Electric light 415, 416-432 

automatic regulators of 417 

adaptation of, for sea-coast lights 418 

intensity of, compared with light from other sources 421 

power of penetrating fogs 422, 424 

power of at La Heve 422, 423 

practicability of extending the system of electric illumination to coast 

lights generally 426 

economy of, compared with light from other sources 421 , 425 

Electric brakes for rail cars - 273 

Electric telegraph, the effect of the invention of, on the moral and intellectual 

character of the human race 19 

Electric telemeters 587 

42i A 



658 INDEX. 

Page. 

Electro-balistic pendulum of Captain Navez 564 

Colonel Benton 565 

Electro-chronoscopes 563 

Electro-chronoscope of Captain Navez 564 

Electro-magnetic engines, advantages of 1 25 

Cazal's 125 

Birmingham Company's ]26 

Kravogl's, (note) 127 

Electro-magnetic machine, exhibited by the British government 418 

Electro-magnets 561 

Electrostatical apparatus , 545 

Elevator, hydraulic, of Mr. Edoux 205 

Enamels, Pleischl's, use of, for various purposes 327 

photograph 467 

Engraving, the polypantograph 461 

by electricity ' 461 

Dulos's method 463 

heliography 464 

Envelope-folding machines 261 

Ericsson, hot-air engines of 34 

Evaporator, universal, Chenailler's 277 

Evaporation, under diminished pressure 364 

tendency to, at all temperatures 363 

E vrard's rotary compression blower 1 93 

machine for compressing coal dust 310 

Evrard &. Boyer's butt-making machine 250 

F. 

Fagersta Steel Works, Sweden 5S9 

Feeders for boilers 232-236 

Fermentation, control of, by artificial refrigeration 390 

Ferro-manganese 291 

Fizeau's process of heliography 465 

Flames, acoustic 509 

Flamm's typographic compositor. 449 

Flashing light at Wicklow Head 409 

Fly-wheels, accumulation of force in 153-155 

Folding machines for paper and for envelopes '2b9. '261 

Foucault's calcite polarization prism 526 

isochronal regulator 531 

Formis's wind-mill 120 

Franchot, hot-air engine of 54 

Freezing apparatus, Carre's sulphuric acid 367 

ammoniacal, intermittent 370 

economy of Carre's ammoniacal, cost of ice produced by 374 

contiuuous freezing apparatus 375. 377 

Twining's invention of 376. 393 

use of, for extraction of potash from sea water 387 

continuous, description of F. Carre's continuous 377- - 

cost of ice produced by 353. 3^4 

first experiments with Twining's 399 

economy of producing ice by Twining's apparatus 400 

Freezing mixtures, cause of the cold produced by 302 

Friction matches, machines for makiu g 263 



INDEX. G59 

Page. 

Frot, Mr., ammoniacal gas engine of 73 

Fuel, artificial 309 

Furnaces, Siemens's regenerating furnace 351-356 

G. 

Galvanoplasty, application of 22 

Galvanic batteries, Daniells's, Smees's, Farmer's, and others 555-559 

Thomsen's polarization battery 559 

Gas-light for light-houses 404 

relative cost of gas and oil 409, 4 1 4 

estimate of cost of introducing 413 

Gas meters 229 

Gauge lathe, Whitney's 242 

Gautier's telemetrical telescope . 592-594 

Gaveaux, Mr. A. Y., of Paris, printing press of 433 

Gay-Lussac, law of, discussion of, (note) 146 

Geissler, air-pump of, without valves 490 

tubes of . 56 1 

Gerbert, hydraulic organ of I 631 

calculating machines of 632 

Gilding and bronzing of printed characters 440 

Girard's turbine 114 

hydraulic pivot 118 

turbine elevator 189, 190 

"palier glissant," or frictionless support 208,211 

Glass, production of, in the Siemens furnace 353 

Feil's exhibition of the silico-borate of lead 521 

for optical purposes 520-521 

large plates of, exhibited by the St. Gobain Company 52 1 

Glaze for casks, Werner's 328 

Gouin & Co. , use of water under heavy pressure in tunneling 151 

Gorrie, Dr. John, note on papers by 402 

Grain weigher, automatic, Pooley's 276 

Great Britain, influence of the early possession of the steam-engine on the wealth 

and power of 15 

Gregg's brick-pressing machine 252 

Grillet, construction of a calculating machine 634 

Grindstones, artificial, made by Eansome's process 307 

Gunter's logarithmic scale 635 

Gwynne & Co., Messrs., centrifugal pump of 177-183 

H. 

Hardy's micro-pantographic instruments 617 

Hartnack's polarization prism 525 

Heat, transportation of, for economical purposes 346 

improvements in the application of 346 

unit of reference for quantities transferred from one body to another 369 

Heating apparatus, Joly de Marval's 346 

Helmholtz, Prof. H. , double siren of 50 1 

resonator of 502, 503 

Heliography 464 

Henry, Prof. Joseph, apparatus for recording the velocity of projectiles 564 

Hertel's plastic-clay brick machine 253 



660 INDEX. 



Hirn,C.F, telodynamic cable of 129-134,149 

construction of pulleys for support of the cable of 131 

applications of cable of 131 

loss of power attendant upon use of cable of 133 

Hirn,G A , pandynamorueter of 166 

methods employed by, for measuring force 166 

importance of invention of, to mechanical engineer 168 

Hinge-making machine, Evrard & Boyer's 250 

Hoe's printing presses 436 

Hoffman's annular brick furnace 357 

number in operation in Germany and England 359 

Hoglen & Grafflin's tobacco-cutting machine 254 

Holtz's electrostatic induction machine 551 

Houget & Teston's boiler feeder 233-236 

Hot-air engines, advantages and disadvantages of 26 

theoretic limit of the economy of 27 

regenerators in 33 

Ericsson's 34 

relative motion of pistons of 39 

Shaw's 41 

Belou's 45 

Eoper's 48 

experiments of Messrs. Tresca and Alcan 46 

Lauberau's 50 

Wilcox's 53 

Franchot's 54 

Huelgoat, example of transmission of force at 129 

Hugon, Mr., inflammable gas-engine of 66 

Hydraulic elevators 1 69 

display of, at the Exposition 169 

" ascenseur Edoux " 204 

Hydraulic elevators, advantages of, for dwellings 207 

Hydraulic engines, construction and application of 99 

description of, at Huelgoat, by Mr. Delaunay 100 

Carret, Marshall & Co. 's water-engine 101 

Perret's water-engine 102 

Coque's water-engine 1 05 

Eamsbottom's water-engine 106 

Hydraulic presses, recent improvements in 196 

Chollet-Champion's 196 

Desgoffe and Ollivier's sterhydraulic apparatus 198 

Hydro-aero-dynamic wheel, invention of, by Mr. Calles 134 

construction and advantages of 135 

mechanical principle involved in 1 35 

Hydro-electric batteries • 555 

I. 

Ice, artificial production of 366 

artificial production of, at the Exposition 36S 

cost of, produced in F. Carre's continuous freezing apparatus 384 

economical production of, by Twining's apparatus 401 

Ice-apparatus of Mr. E. Carre, description of 36T 

cost of 368 

Twining's American 395 

Induction coils exhibited by Ruhmkorff 56 1 



INDEX. GG1 

Page. 

Inflammable gas-engines, principle of construction of .">(; 

early efforts in construction of 57 

Lebou's 58 

Johnson's 59 

number of, at Exposition 60 

Otto and Langen's GO 

experiments in regard to, by Professor Karl Jenny, of 

Vienna 62 

Lenoir's 63 

experiments in regard to, by Mr. Tresca 65 

Hugon's 66 

disadvantages of 70 

Inventions, classification of 20 

J. 

Jamin, apparatus for measuring difference of phase in undulations 526 

Jenny, Prof. Karl, experiments of, in regard to gas-engines 62 

Johnson, James, inflammable gas-engine of 59 

Johnson's deep-sea pressure gauge 608 

Joret, Mr. H., of Paris, patent bridges of 294 

K. 

" Klangfarbe," or sound color 502 

Kcenig, Mr. Rudolph, of Paris, exhibition of acoustic apparatus 49 

nodal point manometric flames 512 

clang-analyzer of 513 

Knee-joint press, Samain's 216 

Kravogl, M., electro-magnetic engine of 126, 127 

mercurial air-pump of 492 

Krupp's exhibition of large ingots and forgings of cast steel 283 

L. 

Lacolonge, M. Ordinaire de, paper by, on Perret's water-engine 103 

Lacy's door opening both ways 280 

Ladd's dynamo-magneto-electric machine 426, 427 

La Heve, sea-coast lights at 422 

electric light at 422 

Latent heat 363 

Latent heat of water 370 

Lauberau, hot-air engine of 50 

Laurent's sextant, for stellar observations 599 

Lebou, gas-engine invented by, in 1799 58 

Leclanches improved carbon battery , 55! ' 

Leibnitz, efforts to construct a calculating machine 635 

Lemonnier and Nouvion's portable press 214 

Lenoir, Mr., inflammable gas-engine of 63 

experimental results with engine of 65 

Levelling instruments 597 

Life-saving respiratory apparatus 344 

Light-houses, exhibition of, at Paris 403 

use of gas-light for 404 

Dublin Ballast Board . 405 

Bailey light-house 1< •"> 

Light-house illumination 1 1 •"> 



662 INDEX, 

Page. 

Light, electric, for light-houses 418 

Lissaj oil's comparator 508 

Lithography 456 

Lithographic printing rollers 460 

Lloyd's noiseless fan 1 91 , 1 92 

Locke, Prof., electro-chronograph 563 

Lorieux's binocular tele metric marine-glasses 578 

Lowe, Mr. T. C. S., patent ice machine 397 

Lotte's portable wine press 214 

Lundin's arrangement for cooling gases of the Siemens furnace 353 

M. 

Machine tools, effect of the invention of the steam-engine on 14 

Magneto-electricity, use for illumination 416-432 

automatic regulators for the electric light 417 

adaptation to sea-coast light 418 

Magneto-electric mac bines, exhibition of, at Paris 418 

description of 419 

machines at La H&ve 422 

probable reduction in cost of 426 

Ladd's machine 426 

Wilde's machine 429 

Mahoudou's windmill 120 

Mahovos, the, a contrivance to promote economy in railway transportation 153 

construction of, described 1 55 

advantages to be derived from its use 156-159, 160 

employed as a brake 159-1 60 

model of, at Exposition 161 

Manometric flames— tubes in unison 513 

Marcus, Prof. S. , thermo-electric battery of 560 

Marine-glasses, binocular telemetric 57S 

Mariotte, law of 146 

Marval's, Joly de, heating apparatus 346 

Matches, friction, machines for making 263 

Mazeline's machine for making agglomerated coal 310 

Measuring rules 613 

Mechanical presses 212 

Mechanical calculation 629 

Mechanical broom for sweeping streets 275 

Metallography 459 

Meteorograph, by Father Secchi 571 

Meteorological registering apparatus o^0, 570. 57 5 

Meters, for liquids , 219 

for gas 228 

constant-level gas-meter 229-232 

Metrology and mechanical calculation 613 

Micrometric apparatus, Whitworth's 12 

Micrometry 613 

Micrometers, substitute tor spider lines in 53 1 

Micro-pantographs 617 

Microscopes 532 

Hoffman's polarization microscope 533 

exaltation of resolving power 533 

objectives of Powell and Lealand 



INDEX. 663 

Page. 

Microscopes, Hartnack's objectives 533, 536 

principal constructors of 5:54 

improvements in the form and accessories of 534 

cheapness of microscopes made by Lebrun 535 

Lister's "double correction" objectives 53C 

immersion lenses 537 

objectives of Messrs. Tolles and Wales 537, 544 

binocular microscope by Nachet 539 

stereotomic 541 

Smith's catadioptric binocular 542 

double, for two observers 543 

triple, for three observers 543 

stands of microscopes 544 

Microscope objectives, Tolles 47 1 

Microscopic drawings and designs on glass G19 

Millstones, machine for dressing 251 

Aubin's improved 279 

Minehin, Mr., exhibition of samples of sugar 325 

Mitchell's composing machine 452 

Moerath, Mr., construction and advantages of windmill of 122 

Morin, General, machine of, for illustrating the laws of falling bodies 488 

Morse, Messrs. Sidney E. and G. Livingston, bathometer of 609 

Motay, Tessie de, specimens of heliographic engraving 466 

Motors, classification of 26 

Mount Cenis, use of compressed air at 1 37, 142, 1 43 

Musina, Opprandino, pocket machine of 637 

N. 

Nachet's binocular microscope 538 

t ) microscope 543 

Nail-making machine, Wickershain's 248 

Napier's rods 633 

Nautical compasses 603, 604 

Neut & Dumont, Messrs., centrifugal pump of 183 

Niagara Falls, waste of power at 129 

Normand's improvement for producing reciprocating motion in presses 434 

O. 

Oils, extraction of, by means of sulphide of carbon 317 

removal of, from wool 317 

Oil and gas, relative cost of, for light-houses 410, 414 

Optical glass 520, 521 

Otto & Langen, inflammable gas-engine of 60 

Ovens, heating of, by Marval's heating apparatus 349 

P. 

' ' Palier glissant, ' ' or frictionless support 208 

Panicography 456 

Pandynamometer, Hirn's 165-168 

Paper, materials for the manufacture of 312 

beautiful samples from Japan 313 

machine for making wood pulp 314 

chemical treatment of materials for 315 

Kachet & Machard's process 316 



664 INDEX. 

Page. 

Paper-folding machi ves 259 

Papier-mache for stereotype molds 44*2 

Pai kesine and its uses 330 

Pascal, calculating machine of 634 

Payton's meter for liquids 224 

Perret, Mr. F. E., water-engine of 102 

paper on water-engine of, by M. Ordinaire de Lacolouge J03 

Pencil-making machine 247 

Perm's band saw 245 

Perreaux, Mr. , valve pump of 174 

Perreaux's circular dividing machines 613 

Perkin's, Jacob, first arrangement for economical production of ice 395 

Peters's micro-pantograph . 613 

Phonautograph, Scott & Kcenig's 506 

Phosphorescence, phosphorescent powders 527 

Photographs, Eutherfurd's photograph of the spectrum 529 

Photograph enamels 467 

Photo-lithography 466 

Photometric gas-measuring apparatus 229 

Pillner & Hill, rotary steam-engine of 85 

Pistor and Marten's circle 598 

Planetarium, Barlow's 471 

Planimeter, Oppikoffer's 620, 621 

Amsler's 623, 624 

Amsler's, theory of 625-629 

Pleischl's enamels and calking pitch 323 

Poirier's match-box-making machine 265 

Pooler's automatic grain-weigher 276 

Poisson, equations of ] 46 

Polaristrobometer 525 

Polarization apparatus 523 

Hoffman's polarization microscope 523 

Hartnack-Prazmowski polarization prism 525 

Polypantograph 461 

Potash, extraction of, from sea-water by refrigeration 387 

Presses, mechanical 215 

printing presses , 433-43S 

Pressure gauge for deep-sea sounding, Johnson's 608 

Printing presses, display of, at the Exposition 433 

Alauzet's improved press 433 

Normand's improved reciprocating motion 434 

for printing in colors 436 

rotary presses 436 

Bullock's rotary press 437 

for numbering bank notes 438 

effect of the invention of 18 

Prisms, exhibition of, by various makers 5'22 

Foucault's polarization 526 

Silbermann's, of variable angle for fluids 522 

Prism telemeters 589 

single telescopes 593 

Projectiles, velocity of, recorded by electro-chronography 564 

Prony, Mr., friction dynamometer of 163 

Protte's turbines 113 



INDEX. 665 

Page. 

Pumps, Earle's steam pump 170 

Schabaver & Foures's pompe castraise 1 70 

Perreaux's 17 1 

centrifugal 177-190 

Puddling iron and steel in the Siemens furnace 356 

Punching steel rails by hydraulic pressure 212 

Pyrometers, Wedgewood's and others 518 

Becquerel's thermo-electric 519 

Pyrostereotypy 456 

R. 

Rachet & Machard's process for manufacture of paper 316 

Radiation, a cause of depression of temperature 365 

Ramsbottom &■ Co., Messrs., water-engine of 106 

advantages of water-engine of 1 08 

Ransome artificial stone 303, 304-308 

application of 306 

grindstones made of 307 

Reflecting instruments 598 

Regenerators, construction and advantage of in hot-air engines 33 

Regenerating furnace, Siemens's 351 

Respiratory apparatus, life-saving 344 

Reynolds, Mr. Edward, water-jet elevator of 175 

Richard's air-pump wi thout valves 493 

Rieter's turbine 1 14 

Riedel's boiler-feeder 232 

Rimailho Brothers, of Paris, machine for making friction matches 263 

Ritchie, E. S. , of Boston, mode of winding induction coils ' 561 

Roberts, E. F., esq., letter from, on light-house illumination 411 

Robert's diffusion process for extraction of sugar 322 

Roches Douvres, light-house for, at the Exposition 403 

Rochon's double-image telescope 577 

Rogers, Professor Wm. B. , revolving gas-jet of 510 

Rollers for lithography 460 

Root, Mr., double-piston square engine of 96 

rotary compression blower of 1 93 

Rotary pumps, advantages of 176 

Rotary printing presses 436 

Rotary steam-engines, advantages of 82 

difficulties of construction of 82 

Behrens's 83 

Pillner & Hill's 85 

Thompson's 87, 649 

Scheutz's 93 

Breval's 95 

Root's double piston square engine 96 

Roper, hot-air engine of 48 

Rouquayrol & Denayrouze, diving apparatus of 338 

Ruhmkorff 's electro-magnet 561 

induction coils 561 

Rutherfurd, Mr. Lewis M., photograph of the solar spectrum. „ 529 

photographic view of the moon 529 



666 INDEX. 

s. 

Page. 

Saccharimeter, the Hoffmann-Wild 525 

Safety -brakes for rail cars 272 

Samain's knee-joint press 216 

use of this press as a dynamometer 217 

Sehabaver & Fonres's pompe castraise 170 

Schaffgotsch, singing flames, apparatus of 511 

Scheutz, rotary steam-engine of 93 

Scheibler's tonometer 504 

Scbiele's turbine 114 

compound blowing fan.-, 192 

Schlickey sen's brick machine 254 

Schlosser s brick machine 254 

Schmerbor Brothers' brick machine 254 

Schmidt, Mr. G. , of Paris, machine for dipping friction matches 263 

Schultz's electro-chronoscope 567 

Schuberszky, Captain Carl Yon, invention of the Mahovos 153 

Screws for fastening the soles of shoes 256 

Seal presses made by Desgoffe & Ollivier 202 

Secchi, Rev. Fatber, sustaining battery by 558 

Secchi's meteorograph 571 



balance barometer. 



572 

Sellers's machine tools 238, 239 

Sextants 598 

Pistor & Marten's 598 

Laurent's, for stellar observations 599 

Davidson's spirit level 600 

Shaw, hot-air engines of 41 

Shoe-making machines . . 255 

Siemens, Messrs., engine of 70 

Siemens's regenerating furnace 35 L 

modified for the production of flint glass 356 

used for reheating blooms and forgings . . 356 

conversion of pig-iron into steel in 354 

Lundin's modification 353 

Siemens's electro-chronoscope 567 

Silberman, Mr. J. C. opinion expressed of balances from the United States 4~-~i 

Silicate of soda, use of in the manufacture of artificial stone 304 

Siren of Professor Helmholtz 501 

Smith, Professor Hamilton L., catadioptrie binocular microscope of 542 

Sorensen's machine for distributing type 455 

Soleil, exhibition of polarization apparatus by 523, 526 

Sounds, visible illustration of interference of 512 

Sounding, deep-sea 605 

Trowbridge's apparatus for 605 

without a line 60? 

the bathometer 609 

Spectroscopes, exhibition of, by Mr. Duboscq 527 

Hoffmann's direct vision 

Spectrum, Rutherfurd's photograph of - 589 

Spherometers, 614 

Spirit meter of Siemens & Halske 210 

Stadimeter, Peaucellier & Wagner's 510 

Staffel, calculating machine of 644 



INDEX. 667 

Page. 

Steam-engine, industrial revolutions resulting from the invention of 7 

increase of power of constructive art by invention of 14 

influence of, on the wealth and power of Great Britain 15 

Steam pump, Earle's 169 

Steam, latent heat of 364 

Steel, the production of 281 

magnitude of later improvements in the manufacture of 281 

origin and progress of the manufacture of 282 

natural, of Corsica and Catalonia 282 

Huntsman's improvement of, in 1740 282 

puddled 283 

production of large masses, by Krupp 283 

Bessemer's process 284 

production of, from the ore, by Siemens's process 297 

production of, in the Siemens furnace 355 

direct from pig-iron 353 

Steel plates, for ship-building 289 

Steel rails, Bessemer, use of, in Austria and France 293 

Steinheil,of Munich, exhibition of glass prisms by 522 

Stenallactic telescope, Porro's 580 

theory of 581,582,583 

Stereotyping, substitution of clich6s for movable type 441 

Sterhydraulic apparatus, construction of 1 98 

formula of power of 202 

various applications of 203 

Strise detector, Topler's 522 

Stone, artificial, Ransome's 303 

Submarine armor, Klingert's 332 

Tonkins 332 

and breathing apparatus 337 

Submarine Company, of New York, apparatus of 336 

Submarine lamp 338 

Sugar, Roberts's diffusion process for the extraction of 322 

Sugar-cutting machine, Devisseber's - 265 

Suggs's photometric gas-measuring apparatus 229 

Sulphuric acid apparatus for freezing water 366 

Support, frictionless, Girard's 208 

Sweet's stereotype matrix machine- 443 

T. 

Tailfer's mechanical broom 275 

Taurine, Mr., dynamometer of 163, 164 

method of registering used by - 164 

Tele metrical apparatus ' 576 

Telemeters, electric 587 

prismatic 589 

Telemetric double telescopes 584-587 

Telemetric binocular marine glasses 578 

Telescopes 529 

reflecting, by Secretan, of Paris 531 

compact pocket 530 

telemetric double 584 

Tellier, Mr. Charles, refrigerating apparatus for breweries 393 

Telodynamic cable, invention of, by Mr. Hirn 130 

construction and advantages of 132 



668 INDEX. 

Page. 

Telodynamic cable, percentage of t>e power delivered by 133 

Tensile strength of wire, apparatus for testing 203 

Terra-cotta, adaptation of Hoffman's brick furnace to baking of 358 

Theodolites 595 

Dabbadies' 596 

Thermometers 516 

mercurial minimum, Casella's '. 517 

self-registering 573 

Thermo-electric batteries £ 59 

Tuition's windmill 120 

hydraulic pressure blower 193-195 

Thomas's arithmometer 633 

solution of problem of calculating machine 636 

Thomas, calculating machine of 636 

Thompson, Mr., rotary steam-engine of 87, 649 

tuibine of 117 

Thomsen's polarization battery 559 

Tillman's tonometer 471 

proposed cheinical nomenclature 478-461 

Tobacco-cutting machine 254 

Tolles, Mr. R. B., microscope on the stereotomic principle 54 1 

Tolles's microscope objectives 471-537 

Tolles & Wales's microscope objectives 537 

Tonometer, Scheibler's 504 

Tillman's 471 

Topler's striae detector 522 

electrostatic induction machine 549 

Transmission of force to great distances 128, 129 

by compressed air 1 35, 136 

Tresca & Alcan, Messrs., experiments of in regard to hot-air engines 46 

Tresca, Mr., experiments of in regard to inflammable gas-engines 65 

comparator of 615 

Trowbridge's deep-sea soundiug apparatus 607 

Turbines, Euler's investigation of the theory of 109 

construction of Mr. Fourneyron's 1 10, 650 

Girard's free turbine Ill 

Fontaine's turbines 1 12 

Brault & Bethouard's 112 

Protte's 113 

Tucker's bronzed iron 329 

Tulpin's machines for drying cloths, yarns, &c 27 1 

Turbine elevator, for water, Girard's 189, 190 

Twining, Professor Alexander C, continuous freezing apparatus of 370. 395 

ice-apparatus, economy of 401 

Type, machine for dressing 439 

improvements in movable 45 1 

machine for distributing 455 



Valve pumps 169 

Varley 's static induction apparatus 540 

Ventilation by aid of refrigerating -app iratus 39 1 

Vibrations, graphic representation of 506, 507 . 508 

Vibroscope, Wesselhoft's u aiversal 515 



INDEX. 662 

Page. 

Voelter, Henry, of Wurtemberg, machine for making wood pulp 313 

Volumeter of Siemens & Halske 219 

W. 

Water-wheels, display of at Exposition 108 

Mr. Sagebien's 109 

' Mr. Colladon's floating wheel 109 

Water-meter of Mr. E. Duboys 222 

of Mr. J. A. Clement 224 

of Mr. Cochrane, United States 225-228 

Werner's patent glaze for casks 328 

Wesselhoft's universal vibroscope 515 

Wheatstone, Professor, experiments upon the power of one magneto-electrical 

machine to excite magnetism in another 431 

apparatus of, for recording velocity of projectiles 564 

Whitney's gauge lathe 242 

machines for working in wood 244 

Whitworth, Mr. , micrometric apparatus of 12 

Whitworth's apparatus for subjecting steel to pressure during casting 212 

Wicklow Head, gas-lighting at 412 

Wickersham's nail machine 248 

Wigham's gas-light for light-houses 404-412 

Wilde's magneto-electric machine 429 

Wilcox, hot-air engine of 35 

Windmills 120-125 

Wind registers, Beck's, of London 571 

Wine press, Lotte's portable. 214 

Wood pulp for the manufacture of paper 313 

woods best adapted to the production of 31 5 

Word-working tools, excellence of, from the United States 245 

Wool, removal of oils from 318 

Moisson's apparatus for removal of oil from 317 

Z. 

Zollner's astrophotometer 530 



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